get query variable

README.md

use like this:

getQueryVariable("foo")

To get variables in urls eg:

http://foo.com/index.html?foo=bar

If you want to support arrays, check the version by @atk below:

annotated.js

function(a){
	return RegExp("[&?]"+a+"=([^&]+)").exec(location)[1]
}

//searches the url (location)
//finds the text after a "&" or a "?" followed by the variable name, followed by a "="
//and before another "&"

index.js

function(a){return RegExp("[&?]"+a+"=([^&]+)").exec(location)[1]}
//If you want to support arrays (Thanks atk!)
function(a){for(var b=[],c,d=eval('/[&?]'+a+'(\\[])?=([^&]+)/g');c=d.exec(location);)b.push(c[2]);return b}

package.json

{
  "name": "getQueryVariable",

  "description": "Get variables in urls",

  "keywords": [
    "url",
    "query",
    "string",
    "variable",
    "get"
  ]
}

test.html

<script>
getQueryVariable = function(a){return RegExp("[&?]"+a+"=([^&]+)").exec(location)[1]}

document.write(getQueryVariable("foo"))
</script>

&|\\? will not work properly, as it will match either "&" or "?[identifier=]", therefore returning the whole [identifier]=[value] string if it is preceded by "&". A working version would be:

function(a){return(RegExp('[&?]'+a+'=([^&;]+)').exec(location)||0)[1]}

&|\\? will not work properly, as it will match either "&" or "?[identifier=]", therefore returning the whole [identifier]=[value] string if it is preceded by "&". A working version would be:

function(a){return(RegExp('[&?]'+a+'=([^&;]+)').exec(location)||0)[1]}

@atk
Wow! I made a stupid mistake there =P
That code is very smart!
I didn't know that exec can reference stuff in parentheses! What a noob I am!

@atk
Wow! I made a stupid mistake there =P
That code is very smart!
I didn't know that exec can reference stuff in parentheses! What a noob I am!

@williammalo: we live and learn :-)

@williammalo: we live and learn :-)

What about using split with regex?

What about using split with regex?

The original code did, but exec is much smaller.

The original code did, but exec is much smaller.

What about supporting array values (e.g. x[]=1&x[]=2)?

What about supporting array values (e.g. x[]=1&x[]=2)?

@FarSeeing
I'm sorry but I have no idea what you mean by that.

@FarSeeing
I'm sorry but I have no idea what you mean by that.

@williammalo
The current version throws an error, if you try to search for array parameters:

// location = 'http://example.com?a=1&b[]=2&b[]=3'
getQueryVariable = function(a){return RegExp("[&?]"+a+"=([^&]+)").exec(location)[1]}
getQueryVariable( 'a' ); // "1", correct
getQueryVariable( 'b' ); // TypeError: RegExp("[&?]" + a + "=([^&]+)").exec(txt) is null
getQueryVariable( 'b[]' ); // TypeError: RegExp("[&?]" + a + "=([^&]+)").exec(txt) is null

@williammalo
The current version throws an error, if you try to search for array parameters:

// location = 'http://example.com?a=1&b[]=2&b[]=3'
getQueryVariable = function(a){return RegExp("[&?]"+a+"=([^&]+)").exec(location)[1]}
getQueryVariable( 'a' ); // "1", correct
getQueryVariable( 'b' ); // TypeError: RegExp("[&?]" + a + "=([^&]+)").exec(txt) is null
getQueryVariable( 'b[]' ); // TypeError: RegExp("[&?]" + a + "=([^&]+)").exec(txt) is null

A version which supports array:
function(a,b,c){with(eval('/[&?]'+a+'(\\[])?=([^&]+)/g'))for(b=[];c=exec(location);)b.push(c[2]);return b}

A version which supports array:
function(a,b,c){with(eval('/[&?]'+a+'(\\[])?=([^&]+)/g'))for(b=[];c=exec(location);)b.push(c[2]);return b}

Those TypeErrors can be caught with a (...||0)[1] construct as in my proposal.

Those TypeErrors can be caught with a (...||0)[1] construct as in my proposal.

@tsaniel
If you can make a version without "with" I'll update my function. (I have withophobia)

@tsaniel
If you can make a version without "with" I'll update my function. (I have withophobia)

Only 1 char longer:
function(a){for(var b=[],c,d=eval('/[&?]'+a+'(\\[])?=([^&]+)/g');c=d.exec(location);)b.push(c[2]);return b}

Only 1 char longer:
function(a){for(var b=[],c,d=eval('/[&?]'+a+'(\\[])?=([^&]+)/g');c=d.exec(location);)b.push(c[2]);return b}

@atk
Great! it works perfectly! (I think...)
I'll put it in my gist!
Thanks!

@atk
Great! it works perfectly! (I think...)
I'll put it in my gist!
Thanks!

If you have an anchor on url like param=value#anchor it returns the value like value#anchor, you just need to add one more byte to the code to works =D

function url(a){for(var b=[],c,d=eval('/[&?]'+a+'([])?=([^&^#]+)/g');c=d.exec(location);)b.push(c[2]);return b}

If you have an anchor on url like param=value#anchor it returns the value like value#anchor, you just need to add one more byte to the code to works =D

function url(a){for(var b=[],c,d=eval('/[&?]'+a+'([])?=([^&^#]+)/g');c=d.exec(location);)b.push(c[2]);return b}