Javascript: Get variables from querystring

rbosinger — Fri, 19 Sep 2008 17:31:55 +0000

Problem:

You need to grab some information from the querystring of a URL using only javascript.

Solution:

Use some code I found!

I found this code:

/* Client-side access to querystring name=value pairs
	Version 1.2.3
	22 Jun 2005
	Adam Vandenberg
*/
function Querystring(qs) { // optionally pass a querystring to parse
	this.params = new Object()
	this.get=Querystring_get
 
	if (qs == null)
		qs=location.search.substring(1,location.search.length)
 
	if (qs.length == 0) return
 
// Turn  back to 
// See: http://www.w3.org/TR/REC-html40/interact/forms.html#h-17.13.4.1
	qs = qs.replace(/\+/g, ' ')
	var args = qs.split('&') // parse out name/value pairs separated via &
 
// split out each name=value pair
	for (var i=0;i<args.length;i++) {
		var value;
		var pair = args[i].split('=')
		var name = unescape(pair[0])
 
		if (pair.length == 2)
			value = unescape(pair[1])
		else
			value = name
 
		this.params[name] = value
	}
}
 
function Querystring_get(key, default_) {
	// This silly looking line changes UNDEFINED to NULL
	if (default_ == null) default_ = null;
 
	var value=this.params[key]
	if (value==null) value=default_;
 
	return value
}

So throw that in your page, and then call that sucker like this:

// Parse the current page's querystring
var qs = new Querystring()

And then just go right on ahead and populate some variables with some query string variables:

var v1 = qs2.get("name1")
var v3 = qs2.get("name3", "default value")

And use that information for whatever you needed it for in the first place. Is nice?

Ryan Bosinger » Javascript

Javascript: Get variables from querystring