Question: I am using a drop down for dynamically changing content on a page. It works but is throwing a js error in Chrome ONLY. What Chrome recommends I don't know how to implement. Site is built in ExpressionEngine 2.8.1.

**ERROR MESSAGE IN CHROME**

> 
> Uncaught TypeError: Cannot set property 'onchange' of null functions.js:65  
> 
>  event.returnValue is deprecated. Please use the standard event.preventDefault() instead.
> 
> 
> 

**MY JS Code**

```
document.getElementById("drop").onchange = function() {
    if (this.selectedIndex!==0) {
        window.location.href = this.value;
    }        
};

```

**MY HTML Code**

```
            <form method="post" action="{path='locations/index'}" class="drop">
                <select id="drop">
                    <option>Select a Location:</option>
                {exp:channel:entries channel="locations" category="not 3" orderby="title" sort="asc" dynamic="no"}
                    <option value="{site_url}index.php/locations/{url_title}">{title}</option>
                {/exp:channel:entries}
                </select>
            </form>

```

Answer: 
You are running the JavaScript code before your HTML has rendered.
Use document ready event

```
$(document).ready(function(){

 $('#drop').change(function(){ 
    if (this.selectedIndex !== 0) {
        window.location.href = this.value;
    }
 })

});

```