Retreiving Values from URL Query

QueryString.js

function getQueryStringValue (key) {  
    return decodeURIComponent(window.location.search.replace(new RegExp("^(?:.*[&\\?]" + encodeURIComponent(key).replace(/[\.\+\*]/g, "\\$&") + "(?:\\=([^&]*))?)?.*$", "i"), "$1"));  
  }    
  // Would write the value of the QueryString-variable called name to the console  
  var quer = getQueryStringValue("a");