aspose-com-gists/Aspose.HTML for Python via .NET – How-to Articles

## README.md

      
    Raw
  

              README.md
            
          
    HTML Manipulation & Styling in Python – Practical Examples

This GitHub Gist repository contains Python code examples referenced in the How-to Articles chapter of the Aspose.HTML for Python via .NET documentation. This Gist contains ready-to-use Python code snippets for everyday HTML processing, styling, and transformation tasks. It's ideal for developers who need quick and practical solutions without having to study extensive documentation.
Why This Collection?

Every web developer faces these questions:

"How do I change background colors programmatically?"
"Can I disable scripts before converting HTML to PDF?"
"What's the easiest way to dynamically style table cells?"

Stop searching. Start coding. Each example is self-contained and ready to use.
Styling & Appearance


Example
Description


Background Colors
Change background using inline CSS, internal CSS, or style attributes


Text Colors
Modify text colors for single elements or all paragraphs at once


Conditional Styling
Apply colors dynamically based on data values


Table Styling
Alternate row colors, border customization, cell backgrounds


Border Customization
Different colors per side, combined styling techniques


Security & Control


Example
Description


Disable Scripts
Sandbox configuration to prevent script execution during HTML to PDF conversion


Disable Images
Block image loading for faster processing or privacy protection


Utilities


Example
Description


Unit Conversion
Convert pixels to centimeters and other measurement units


DOM Validation
Check if HTML body is empty or contains content


About Aspose.HTML for Python via .NET

Aspose.HTML for Python via .NET is a powerful library that enables developers to create, edit, manipulate, and convert HTML documents programmatically using Python. The HTML Document Object Model is integrated with embedded formats and specifications such as CSS, HTML Canvas, SVG, XPath, and JavaScript out-of-the-box, which extend the manipulation functionality and rendering quality.
Prerequisites


Python 3.5+
.NET Core / .NET 5+ runtime
Windows, macOS, or Linux
Aspose.HTML for Python via .NET installed from PyPI

How to Use These Examples


Install the Aspose.HTML Python package:

   pip install aspose-html-net


Clone or download this gist to your local machine.
Adjust paths or configuration settings as needed for your environment.
Run your project to see each example in action.

Related Resources


PyPI
Official Documentation
Product page
Blog – Aspose.HTML Product Family
API Reference
Temporary license


## Aspose.HTML for Python via .NET – How-to Articles
Aspose.HTML for Python via .NET – How-to Articles

## Example-AddCssColorStylesInHtml.py
# How to style HTML elements with colors using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-background-color/

import aspose.html as ah

# Create an empty HTML document
document = ah.HTMLDocument()

# Access the existing <head> element
head = document.get_elements_by_tag_name("head")[0]

# Create a <style> element and define CSS rules
style = document.create_element("style")
style.inner_html = """
    body {
        background-color: #f7dba7;
        color: #333333;
    }
    .highlight {
        color: #d35400;
        font-weight: bold;
    }
"""

# Inject the <style> block into the document <head>
head.append_child(style)

# Create a regular paragraph and assign text content
p = document.create_element("p")
p.text_content = "This is a paragraph with default text color."

# Create another paragraph and apply the "highlight" CSS class
highlight = document.create_element("p")
highlight.set_attribute("class", "highlight")
highlight.text_content = "This line uses the .highlight color style."

# Append both paragraphs to the <body> section of the HTML document
document.body.append_child(p)
document.body.append_child(highlight)

# Save the HTML document to a file
document.save("colored-output.html")

## Example-BlockingExternalImages.py
# Disable loading images in HTML with sandbox configuration using Python
# Learn more: https://docs.aspose.com/html/python-net/sandboxing/

import os
import aspose.html as ah
import aspose.html.converters as conv
import aspose.html.saving as sav

# Prepare HTML code and save it to a file
code = "<span style=\"background-image:url('https://docs.aspose.com/html/images/work/lioness.jpg')\">Hello, World!!</span> " \
       "<script>document.write('Have a nice day!');</script>"

output_dir = "output"
os.makedirs(output_dir, exist_ok=True)
html_path = os.path.join(output_dir, "sandboxing.html")
output_pdf = os.path.join(output_dir, "sandboxing-out.pdf")

with open(html_path, "w", encoding="utf-8") as file:
    file.write(code)

# Create an instance of Configuration
with ah.Configuration() as configuration:
    # Mark 'IMAGES' as an untrusted resource
    configuration.security |= ah.Sandbox.IMAGES

    # Initialize an HTML document with the specified configuration
    with ah.HTMLDocument(html_path, configuration) as document:
        # Convert HTML to PDF
        conv.Converter.convert_html(document, sav.PdfSaveOptions(), output_pdf)

## Example-BlockingScriptExecution.py
# How to disable scripts for HTML to PDF conversion using Python
# Learn more: https://docs.aspose.com/html/python-net/sandboxing/

import os
import aspose.html as ah
import aspose.html.converters as conv
import aspose.html.saving as sav

# Define input and output directories
data_dir = "data"
output_dir = "output"
os.makedirs(output_dir, exist_ok=True)

# Create an instance of the Configuration class
with ah.Configuration() as config:
    # Mark "scripts" as an untrusted resource
    config.security |= ah.Sandbox.SCRIPTS

    # Initialize an HTML document with the specified configuration
    html_path = os.path.join(data_dir, "document-with-scripts.html")
    with ah.HTMLDocument(html_path, config) as doc:
        # Convert HTML to PDF
        output_pdf = os.path.join(output_dir, "document-sandbox.pdf")
        conv.Converter.convert_html(doc, sav.PdfSaveOptions(), output_pdf)

## Example-ChangeBackgroundColorForParagraph.py
# Change background color for HTML paragraph using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-background-color/

import os
import aspose.html as ah

# Prepare output path for document saving
output_dir = "output/"
os.makedirs(output_dir, exist_ok=True)
save_path = os.path.join(output_dir, "change-background-color-p-inline-css.html")

# Prepare path to the source HTML file
data_dir = "data/"
document_path = os.path.join(data_dir, "file.html")

# Create an instance of an HTML document
with ah.HTMLDocument(document_path) as doc:
    # Find the first paragraph element
    paragraph = doc.get_elements_by_tag_name("p")[0]

    # Set the style attribute with background-color property
    paragraph.set_attribute("style", "background-color: #fff0f5;")

    # Save the modified HTML document to a file
    doc.save(save_path)

## Example-ChangeBackgroundColorForTableCells.py
# Change background color for table cells using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-background-color/

import os
import aspose.html as ah

# Prepare directories
data_dir = "data"
output_dir = "output"
os.makedirs(output_dir, exist_ok=True)

# Input and output paths
document_path = os.path.join(data_dir, "table.html")
save_path = os.path.join(output_dir, "change-table-cell-background.html")

# Create an instance of the HTML document
with ah.HTMLDocument(document_path) as doc:
    # Select all <td> elements
    cells = doc.get_elements_by_tag_name("td")

    print("Found cells:", cells.length)

    # Loop through each table cell and set alternating background colors
    for i in range(cells.length):
        cell = cells[i]
        color = "#f3d2dd" if i % 2 == 0 else "#ffffff"
        cell.set_attribute("style", f"background-color: {color};")

    # Save the modified HTML document
    doc.save(save_path)

print("Saved to:", save_path)

## Example-ChangeBackgroundColorWithInlineCss.py
# Change background color with inline CSS using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-background-color/

import os
import aspose.html as ah

# Define the output path for saving the document
output_dir = "output/"
save_path = os.path.join(output_dir, "change-background-color-inline-css.html")

# Define the path to the source HTML file
data_dir = "data/"
document_path = os.path.join(data_dir, "file.html")

# Create an instance of an HTML document
document = ah.HTMLDocument(document_path)

# Find the <body> element to set a style attribute
body = document.get_elements_by_tag_name("body")[0]

# Set the style attribute with background-color property
current_style = body.get_attribute("style") or ""
new_style = current_style + "background-color: lavenderblush"
body.set_attribute("style", new_style)

# Save the HTML document to a file
document.save(save_path)

## Example-ChangeBackgroundColorWithInternalCss.py
# Change background color for HTML using internal CSS using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-background-color/

import os
import aspose.html as ah

# Define paths
output_dir = "output/"
save_path = os.path.join(output_dir, "change-background-color-internal-css.html")
data_dir = "data/"
document_path = os.path.join(data_dir, "file.html")

# Create an instance of an HTML document
document = ah.HTMLDocument(document_path)

# Find the <body> element
body = document.get_elements_by_tag_name("body")[0]

# Remove the background-color property from the style attribute
current_style = body.get_attribute("style") or ""
updated_style = " ".join(prop for prop in current_style.split(";") if not prop.strip().startswith("background-color"))
body.set_attribute("style", updated_style)

# Create a <style> element with CSS rules for the background color
style = document.create_element("style")
style.text_content = "body { background-color: rgb(255 240 245) }"

# Find the <head> element and append the <style> element
head = document.get_elements_by_tag_name("head")[0]
head.append_child(style)

# Save the HTML document to a file
document.save(save_path)

## Example-ChangeBorderColorForFourSides.py
# Change color for four sides of the border using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-border-color/

import os
import aspose.html as ah

# Setup directories and define paths
data_dir = "data"
output_dir = "output"
os.makedirs(output_dir, exist_ok=True)
document_path = os.path.join(data_dir, "file.html")
save_path = os.path.join(output_dir, "change-four-border-color.html")

# Create an instance of an HTML document
with ah.HTMLDocument(document_path) as document:
    # Find the first <h1> element
    header = document.get_elements_by_tag_name("h1")[0]

    # Set inline CSS for border style and different border colors on each side
    header.set_attribute("style", "border-style: solid; border-color: red blue green gray;")

    # Save the modified HTML document
    document.save(save_path)

print("File saved to:", save_path)

## Example-ChangeBorderColorUsingInternalCss.py
# Change border color for HTML using internal CSS in Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-border-color/

import os
import aspose.html as ah

# Setup directories and define paths
data_dir = "data"
output_dir = "output"
os.makedirs(output_dir, exist_ok=True)
document_path = os.path.join(data_dir, "file.html")
save_path = os.path.join(output_dir, "change-border-color-internal-css.html")

# Create an instance of an HTML document
with ah.HTMLDocument(document_path) as document:
    # Create a <style> element and set CSS for <p> elements
    style = document.create_element("style")
    style.text_content = "p {border-style: solid; border-color: rgb(220,30,100); }"

    # Find the <head> element and append the <style> element
    head = document.get_elements_by_tag_name("head")[0]
    head.append_child(style)

    # Save the modified HTML document
    document.save(save_path)

## Example-ChangeHtmlTextColorUsingInlineCss.py
# Change HTML text color using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-text-color/

import os
import aspose.html as ah

# Setup directories and define paths
data_dir = "data"
output_dir = "output"
os.makedirs(output_dir, exist_ok=True)
save_path = os.path.join(output_dir, "change-text-color-inline-css.html")
document_path = os.path.join(data_dir, "file.html")

# Create an instance of an HTML document
with ah.HTMLDocument(document_path) as doc:
    # Find the first paragraph element
    paragraph = doc.get_elements_by_tag_name("p")[0]

    # Set the style attribute with color property
    paragraph.set_attribute("style", "color: #8B0000;")

    # Save the modified HTML document to a file
    doc.save(save_path)

## Example-ChangeHtmlTextColorUsingInternalCss.py
# Change color for all paragraphs in HTML using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-text-color/

import os
import aspose.html as ah

# Prepare an output path for saving the document
output_dir = "output"
os.makedirs(output_dir, exist_ok=True)
save_path = os.path.join(output_dir, "change-text-color-internal-css.html")

# Prepare a path to the source HTML file
data_dir = "data"
document_path = os.path.join(data_dir, "file.html")

# Create an instance of an HTML document
with ah.HTMLDocument(document_path) as doc:
    # Create a <style> element and set CSS for the all <p> elements
    style = doc.create_element("style")
    style.text_content = "p { color: #8B0000 }"

    # Find the <head> element and append the <style> element
    head = doc.get_elements_by_tag_name("head")[0]
    head.append_child(style)

    # Save the modified HTML document to a file
    doc.save(save_path)

## Example-ChangeTableBorderColor.py
# Change table border color using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-border-color/

import os
import aspose.html as ah

# Prepare an output path for saving the document
output_dir = "output"
os.makedirs(output_dir, exist_ok=True)
save_path = os.path.join(output_dir, "change-table-border-color-inline-css.html")

# Prepare a path to the source HTML file
data_dir = "data"
document_path = os.path.join(data_dir, "table.html")

# Create an instance of an HTML document
with ah.HTMLDocument(document_path) as doc:
    # Create a CSS selector to select the first table element
    element = doc.query_selector("table")

    # Set inline style for the selected element
    element.set_attribute("style", "border: 2px #0000ff solid;")

    # Save the modified HTML document to a file
    doc.save(save_path)

## Example-ChangeTableBorderColorUsingInternalCss.py
# Change table border color using internal CSS in Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-border-color/

import os
import aspose.html as ah

# Prepare directories and input and output paths
output_dir = "output"
os.makedirs(output_dir, exist_ok=True)
data_dir = "data"
document_path = os.path.join(data_dir, "table.html")
save_path = os.path.join(output_dir, "change-table-border-color-internal-css.html")

# Create an instance of an HTML document
with ah.HTMLDocument(document_path) as doc:
    # Create a <style> element and set CSS for the <table> element
    style = doc.create_element("style")
    style.text_content = "table { border-style:solid; border-color:rgb(0, 0, 255) }"

    # Find the <head> element and append the <style> element
    head = doc.get_elements_by_tag_name("head")[0]
    head.append_child(style)

    # Save the modified HTML document to a file
    doc.save(save_path)

## Example-ChangeTextColorBasedOnData.py
# Change text color based on data in HTML using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-text-color/

import os
import aspose.html as ah

output_dir = "output"
os.makedirs(output_dir, exist_ok=True)
save_path = os.path.join(output_dir, "conditional-text-color.html")

html_content = """
<html>
<body>
<p>Score: 85</p>
<p>Score: 42</p>
<p>Score: 73</p>
</body>
</html>
"""

# Initialize the HTML document
with ah.HTMLDocument(html_content, ".") as doc:
    paragraphs = doc.get_elements_by_tag_name("p")

    for p in paragraphs:
        text = p.text_content
        score = int(text.split(":")[1].strip())

        # Apply color conditionally
        color = "green" if score >= 70 else "red"
        p.set_attribute("style", f"color: {color};")

    # Save the modified document
    doc.save(save_path)

## Example-ConvertPxToCm.py
# Convert px to cm using Python
# Learn more: https://docs.aspose.com/html/python-net/

import aspose.html.drawing as dr

# Convert 1000.0 pixels to centimeters
px = dr.Unit.from_pixels(1000.0)  # Specify the unit type explicitly
cm = px.get_value(dr.UnitType.CM)  # Convert to centimeters
print(cm)

## Example-HowToChangeBorderColor.py
# Сhange border color for <h1> element using Python
# Learn more: https://docs.aspose.com/html/python-net/how-to-change-border-color/

import os
import aspose.html as ah

# Prepare output directory and path for saving
output_dir = "output"
os.makedirs(output_dir, exist_ok=True)
save_path = os.path.join(output_dir, "change-border-color.html")

# Prepare path to source HTML file
data_dir = "data"
document_path = os.path.join(data_dir, "file.html")

# Create an instance of an HTML document
with ah.HTMLDocument(document_path) as document:
    # Find the first <h1> element
    header = document.get_elements_by_tag_name("h1")[0]

    # Set inline CSS properties
    header.set_attribute("style", "color: #8B0000; border-style: solid; border-color: rgb(220,30,100);")

    # Save the modified HTML document
    document.save(save_path)

## Example-HowToCheckEmptyContent.py
# Check if HTML body is empty using Python
# Learn more: https://docs.aspose.com/html/python-net/

import aspose.html as ah

# Load the HTML document
with ah.HTMLDocument("document.html") as document:
    # Get the body element
    body = document.body

    # Check if the body element contains any non-empty text content
    if body.text_content and not body.text_content.isspace():
        print("Non-empty HTML elements found")
    else:
        print("No child nodes found in the body element.")
Example	Description
Background Colors	Change background using inline CSS, internal CSS, or style attributes
Text Colors	Modify text colors for single elements or all paragraphs at once
Conditional Styling	Apply colors dynamically based on data values
Table Styling	Alternate row colors, border customization, cell backgrounds
Border Customization	Different colors per side, combined styling techniques
Example	Description
Disable Scripts	Sandbox configuration to prevent script execution during HTML to PDF conversion
Disable Images	Block image loading for faster processing or privacy protection
Example	Description
Unit Conversion	Convert pixels to centimeters and other measurement units
DOM Validation	Check if HTML body is empty or contains content
	# How to style HTML elements with colors using Python
	# Learn more: https://docs.aspose.com/html/python-net/how-to-change-background-color/

	import aspose.html as ah

	# Create an empty HTML document
	document = ah.HTMLDocument()

	# Access the existing <head> element
	head = document.get_elements_by_tag_name("head")[0]

	# Create a <style> element and define CSS rules
	style = document.create_element("style")
	style.inner_html = """
	body {
	background-color: #f7dba7;
	color: #333333;
	}
	.highlight {
	color: #d35400;
	font-weight: bold;
	}
	"""

	# Inject the <style> block into the document <head>
	head.append_child(style)

	# Create a regular paragraph and assign text content
	p = document.create_element("p")
	p.text_content = "This is a paragraph with default text color."

	# Create another paragraph and apply the "highlight" CSS class
	highlight = document.create_element("p")
	highlight.set_attribute("class", "highlight")
	highlight.text_content = "This line uses the .highlight color style."

	# Append both paragraphs to the <body> section of the HTML document
	document.body.append_child(p)
	document.body.append_child(highlight)

	# Save the HTML document to a file
	document.save("colored-output.html")
	# Disable loading images in HTML with sandbox configuration using Python
	# Learn more: https://docs.aspose.com/html/python-net/sandboxing/

	import os
	import aspose.html as ah
	import aspose.html.converters as conv
	import aspose.html.saving as sav

	# Prepare HTML code and save it to a file
	code = "<span style=\"background-image:url('https://docs.aspose.com/html/images/work/lioness.jpg')\">Hello, World!!</span> " \
	"<script>document.write('Have a nice day!');</script>"

	output_dir = "output"
	os.makedirs(output_dir, exist_ok=True)
	html_path = os.path.join(output_dir, "sandboxing.html")
	output_pdf = os.path.join(output_dir, "sandboxing-out.pdf")

	with open(html_path, "w", encoding="utf-8") as file:
	file.write(code)

	# Create an instance of Configuration
	with ah.Configuration() as configuration:
	# Mark 'IMAGES' as an untrusted resource
	configuration.security \|= ah.Sandbox.IMAGES

	# Initialize an HTML document with the specified configuration
	with ah.HTMLDocument(html_path, configuration) as document:
	# Convert HTML to PDF
	conv.Converter.convert_html(document, sav.PdfSaveOptions(), output_pdf)
	# How to disable scripts for HTML to PDF conversion using Python
	# Learn more: https://docs.aspose.com/html/python-net/sandboxing/

	import os
	import aspose.html as ah
	import aspose.html.converters as conv
	import aspose.html.saving as sav

	# Define input and output directories
	data_dir = "data"
	output_dir = "output"
	os.makedirs(output_dir, exist_ok=True)

	# Create an instance of the Configuration class
	with ah.Configuration() as config:
	# Mark "scripts" as an untrusted resource
	config.security \|= ah.Sandbox.SCRIPTS

	# Initialize an HTML document with the specified configuration
	html_path = os.path.join(data_dir, "document-with-scripts.html")
	with ah.HTMLDocument(html_path, config) as doc:
	# Convert HTML to PDF
	output_pdf = os.path.join(output_dir, "document-sandbox.pdf")
	conv.Converter.convert_html(doc, sav.PdfSaveOptions(), output_pdf)
	# Change background color for HTML paragraph using Python
	# Learn more: https://docs.aspose.com/html/python-net/how-to-change-background-color/

	import os
	import aspose.html as ah

	# Prepare output path for document saving
	output_dir = "output/"
	os.makedirs(output_dir, exist_ok=True)
	save_path = os.path.join(output_dir, "change-background-color-p-inline-css.html")

	# Prepare path to the source HTML file
	data_dir = "data/"
	document_path = os.path.join(data_dir, "file.html")

	# Create an instance of an HTML document
	with ah.HTMLDocument(document_path) as doc:
	# Find the first paragraph element
	paragraph = doc.get_elements_by_tag_name("p")[0]

	# Set the style attribute with background-color property
	paragraph.set_attribute("style", "background-color: #fff0f5;")

	# Save the modified HTML document to a file
	doc.save(save_path)
	# Change background color for table cells using Python
	# Learn more: https://docs.aspose.com/html/python-net/how-to-change-background-color/

	import os
	import aspose.html as ah

	# Prepare directories
	data_dir = "data"
	output_dir = "output"
	os.makedirs(output_dir, exist_ok=True)

	# Input and output paths
	document_path = os.path.join(data_dir, "table.html")
	save_path = os.path.join(output_dir, "change-table-cell-background.html")

	# Create an instance of the HTML document
	with ah.HTMLDocument(document_path) as doc:
	# Select all <td> elements
	cells = doc.get_elements_by_tag_name("td")

	print("Found cells:", cells.length)

	# Loop through each table cell and set alternating background colors
	for i in range(cells.length):
	cell = cells[i]
	color = "#f3d2dd" if i % 2 == 0 else "#ffffff"
	cell.set_attribute("style", f"background-color: {color};")

	# Save the modified HTML document
	doc.save(save_path)

	print("Saved to:", save_path)
	# Change background color with inline CSS using Python
	# Learn more: https://docs.aspose.com/html/python-net/how-to-change-background-color/

	import os
	import aspose.html as ah

	# Define the output path for saving the document
	output_dir = "output/"
	save_path = os.path.join(output_dir, "change-background-color-inline-css.html")

	# Define the path to the source HTML file
	data_dir = "data/"
	document_path = os.path.join(data_dir, "file.html")

	# Create an instance of an HTML document
	document = ah.HTMLDocument(document_path)

	# Find the <body> element to set a style attribute
	body = document.get_elements_by_tag_name("body")[0]

	# Set the style attribute with background-color property
	current_style = body.get_attribute("style") or ""
	new_style = current_style + "background-color: lavenderblush"
	body.set_attribute("style", new_style)

	# Save the HTML document to a file
	document.save(save_path)
	# Change background color for HTML using internal CSS using Python
	# Learn more: https://docs.aspose.com/html/python-net/how-to-change-background-color/

	import os
	import aspose.html as ah

	# Define paths
	output_dir = "output/"
	save_path = os.path.join(output_dir, "change-background-color-internal-css.html")
	data_dir = "data/"
	document_path = os.path.join(data_dir, "file.html")

	# Create an instance of an HTML document
	document = ah.HTMLDocument(document_path)

	# Find the <body> element
	body = document.get_elements_by_tag_name("body")[0]

	# Remove the background-color property from the style attribute
	current_style = body.get_attribute("style") or ""
	updated_style = " ".join(prop for prop in current_style.split(";") if not prop.strip().startswith("background-color"))
	body.set_attribute("style", updated_style)

	# Create a <style> element with CSS rules for the background color
	style = document.create_element("style")
	style.text_content = "body { background-color: rgb(255 240 245) }"

	# Find the <head> element and append the <style> element
	head = document.get_elements_by_tag_name("head")[0]
	head.append_child(style)

	# Save the HTML document to a file
	document.save(save_path)