This function can be used to use html characters for tags (< and >) inside tags that you specify.

safeparse

// For instance:
// If s = <code><code>This is a nested code that should be replaced</code> <div>Any tag here is replaced</div></code>
// safeparse(s, "code", "code") returns:
// <code>&lt;code&gt;This is a nested code that should be replaced&lt;/code&gt; &lt;div&gt;Any tag here is replaced&lt;/div&gt;</code>
// It should work for any number of correctly written nests.
// This will be applied to all specified top level tags.

// chars is the text to be parsed
// s1 is the starting tag
// s2 is the closing tag

function safeparse(chars, s1, s2)
{
	function replace_string_at(s, c, i, i2=false)
	{
		var ns1 = s.slice(0, i)
		
		var ns2

		if(i2)
		{
			ns2 = s.slice(i2, s.length)
		}

		else
		{
			ns2 = s.slice(i + 1, s.length)
		}

		return ns1 + c + ns2
	}
	
	s2 = `/${s2}`

	var s1b = `<${s1}>`
	var s2b = `<${s2}>`

	var len1 = s1b.length
	var len2 = s2b.length

	let i = 0

	var ncode = 0

	while(i < chars.length)
	{
		if(ncode === 0)
		{
			let index = chars.indexOf(s1b, i)

			if(index > -1)
			{
				i = index + len1
				ncode += 1
			}

			else
			{
				break
			}
		}

		else if(ncode > 0)
		{
			let index = chars.indexOf("<", i)
			let index2 = chars.indexOf(">", i)

			if(index > -1)
			{
				if(chars.slice(index, index + len1) === s1b)
				{
					chars = replace_string_at(chars, `&lt;${s1}&gt;`, index, index + len1)

					ncode += 1
					i = index + len1
					index2 = -1
				}

				else if(chars.slice(index, index + len2) === s2b)
				{
					if(ncode > 1)
					{
						chars = replace_string_at(chars, `&lt;${s2}&gt;`, index, index + len2)
					}

					ncode -= 1

					if(ncode < 0)
					{
						ncode = 0
					}

					i = index + len2
					index2 = -1
				}

				else
				{
					chars = replace_string_at(chars, "&lt;", index)
					i = index + 4
					index2 = chars.indexOf(">", i)
				}
			}

			if(index2 > -1)
			{
				if(index2 < index || ncode > 0)
				{
					chars = replace_string_at(chars, "&gt;", index2)
					i = Math.max(index2 + 4, i)
				}
			}

			if(index < 0 && index2 < 0)
			{
				break
			}
		}
	}

	return chars
}