Reading Query string Values in Javascript

Using simple javascript to get the  query string value of URL.

We have URL as 

<a href="DisplayContent.html?id=0"> 0</a>

<a href="DisplayContent.html?id=1">1</a>

To Read the content of URL you can use below method as;

function getParameterValueByName(name, url) {

        if (!url) url = window.location.href;

        name = name.replace(/[\[\]]/g, "\\$&");

        var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),

            results = regex.exec(url);

        if (!results) return null;

        if (!results[2]) return '';

        return decodeURIComponent(results[2].replace(/\+/g, " "));

    }

Calling this method in next page [DisplayContent]

var ist = getParameterValueByName('id');

Now lets see how we are getting Values.