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]; 
        } 
    } 
    return '';
}