How Do You Get the URL Parameters and Append to Href or Src of Another Element?

Do you want to grab the url parameters and pass them to a button href or iframe src? This is common when you are running a paid ad campaign to a landing page that links to a form on another page. You want to track the source of the form submission by duplicating the url parameters on the form page. Below is the code to help you do that dynamicly.

HTML

<a href="/" id="registerBtn">Register Now</a>

JavaScript

// Apply URL parameters to Register Button if present
var changeTarget = document.getElementById('registerBtn'); 
var params = window.location.search;
var _href = changeTarget.href; 

// Does the page have url parameters ?
if (params) {
    // yes - add them to the iframe src
    changeTarget.href = _href+params;
    console.log("url params = " + params);
} else {
    // no - use a generic iframe src
    changeTarget.href = _href;
}