<p>I run into this quite often where a new page is supposedly "tested" and ready to go. But as soon as I change the page from http to https (secure) mode I get the "This page contains both secure and nonsecure items." error.</p>

<p>Usually I can find the problem and fix it pretty quick. Today is different. I've checked every image reference and every javascript reference and their source and haven't found anything that should be causing this error.</p>

<p>Are there any developer tools or techniques that can point out specifically what is causing this error?</p>

If you're in Firefox you can use Tools -> Page Info -> Media, then just scan down the list to find the non-https link. There might also be JavaScript building dynamic
```
<script>
```
tags, or CSS including non-secure elements.