Using the GET parameter of a URL in JavaScript [duplicate]

If I am on a page such as

http://somesite.com/somepage.php?param1=asdf

In the JavaScript of that page, I would like to set a variable to the value of the parameter in the GET part of the URL.

So in JavaScript:

<script>
   param1var = ...   // ... would be replaced with the code to get asdf from URI
</script>

What would "..." be?

Solution 1:

Here's some sample code for that.

<script>
var param1var = getQueryVariable("param1");

function getQueryVariable(variable) {
  var query = window.location.search.substring(1);
  var vars = query.split("&");
  for (var i=0;i<vars.length;i++) {
    var pair = vars[i].split("=");
    if (pair[0] == variable) {
      return pair[1];
    }
  } 
  alert('Query Variable ' + variable + ' not found');
}
</script>

Solution 2:

You can get the "search" part of the location object - and then parse it out.

var matches = /param1=([^&#=]*)/.exec(window.location.search);
var param1 = matches[1];

Solution 3:

I made this variation of gnarf's solution, so the call and the result is similar to PHP:

function S_GET(id){
    var a = new RegExp(id+"=([^&#=]*)");
    return decodeURIComponent(a.exec(window.location.search)[1]);
}

But as being called in a function slows the process, its better to use as global:

window['var_name'] = decodeURIComponent( /var_in_get=([^&#=]*)/.exec(window.location.search)[1] );

UPDATE

As I'm still learning JS, I created a better answer in a more JS behaviour:

Url = {
    get get(){
        var vars= {};
        if(window.location.search.length!==0)
            window.location.search.replace(/[?&]+([^=&]+)=([^&]*)/gi, function(m,key,value){
                key=decodeURIComponent(key);
                if(typeof vars[key]==="undefined") {vars[key]= decodeURIComponent(value);}
                else {vars[key]= [].concat(vars[key], decodeURIComponent(value));}
            });
        return vars;
    }
};

This allows to be called just using Url.get.

Example The url ?param1=param1Value&param2=param2Value can be called like:

Url.get.param1 //"param1Value"
Url.get.param2 //"param2Value"

here is a snipet:

// URL GET params
url = "?a=2&a=3&b=2&a=4";

Url = {
    get get(){
        var vars= {};
        if(url.length!==0)
            url.replace(/[?&]+([^=&]+)=([^&]*)/gi, function(m,key,value){
                key=decodeURIComponent(key);
                if(typeof vars[key]==="undefined") {vars[key]= decodeURIComponent(value);}
                else {vars[key]= [].concat(vars[key], decodeURIComponent(value));}
            });
        return vars;
    }
};

document.querySelector('log').innerHTML = JSON.stringify(Url.get);

<log></log>