JavaScript URL parameters two ways

A value that takes a parameter from a URL without having to loop purely with a regular implementation. The core technique for replacing loops is that the replace () method of a string can be used as a second parameter and replaced by a user-defined approach.
Returns an empty string if there is a parameter name but no value, and returns undefined if the parameter name is not available.

Call method: var variable name = getparameter ("parameter name to get", url address)
var r = getparameter ("Age", url);

Test output, the result is: site=popasp tutorial
Alert (R);
Depending on the results obtained, you can use
var pname = r.split ("=") [0]; Gets the name of the parameter
var pvalue = r.split ("=") [1]; Get parameter values

Test output:
Alert ("Parameter name:" + pname + "NN" + "parameter value:" + pvalue);

Other practical applications:
According to the need, with the following methods to achieve their own functions;
var hostname = Location.hostname; Get current domain name (does not contain http://)
var localurl = location.href; Get the current complete URL address information (including http://, domain name, path, specific file and all pass parameters)
var referurl = Document.referrer; Get the complete URL information on the previous page (including http://, domain name, path, specific file and all pass parameters)

var getarg = function (argname)
{
var str = location.href;
var Submatch;
First remove the question mark from the URL and the query string between the wellhead and the Http://www.snowpeak.org/testjs.htm?a1=v1&a2=&a3=v3#anchor a1=v1&a2= &a3=v3.
The question mark is a special character of the pattern, so to write?; The well number is dispensable, so the pattern end is #?
if (Submatch = Str.match (/?) ( [^#]*)#?/))
{
Take a captured child match like A1=v1&a2=&a3=v3, add a & &a1=v1&a2=&a3=v3 to the front to make it easier to replace the next
var argstr = ' & ' +submatch[1];
Replace with a function that replaces each set of shapes such as &a1=v1 with a A1: "V1", a property declaration used by such an object definition
var returnpattern = function (str)
{
Matches the 1th and 2nd children captured by the $ and $ representatives, and must be used in a string
Return Str.replace (/& ([^=]+) = ([^&]*)/, ' $: $ ', '];
}
Performs a global regular substitution, the second parameter is the substitution function just defined, replacing the a1=v1&a2=&a3=v3 with A1: "V1", A2: "", A3: "V3",
Argstr = Argstr.replace (/& [^=]+) = ([^&]*)/g, returnpattern);
The final execution of an object's declaration needs to be shaped like var RetValue = {A1: "V1", A2: "", A3: "V3"}; Object declaration, and the end of the string just replaced with a comma, the end of the comma with substr to intercept
Eval (' var retvalue = {' +argstr.substr (0, argstr.length-1) + '}; ');
Now you get an object with the name of each parameter in the URL, and the value of the parameter is the corresponding property.
return Retvalue[argname];
}
}
Test
document.write (' a1= ' +getarg (' A1 ') + ', a2= ' +getarg (' A2 ') + ', a3= ' +getarg (' A3 '));

The following uses the regular processing method

function Geturlparam (name) {
var reg = new RegExp (^|&) + name + = ([^&]*) (&|$));
var r = window.location.search.substr (1). Match (REG);
if (r!= null)
return unescape (r[2]);
return null;
}