Javascript code to get Query string value in sharepoint

var paramID=GetValue('ID');

function GetValue(name)

{

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

var regexS = "[\\?&]"+name+"=([^&#]*)";

var regex = new RegExp( regexS );

var results = regex.exec( unescape(window.location.href) );

if( results == null )

return "";

else

return results[1];

}