Question: I am attempting to debug external JavaScript within a tag on an iframe on a website that I do not have access to the source code. I am able to debug all of the javascript files directly but not the javascript embedded within the HTML. 

I have attempted to search for the code within the sources tab and I am unable to come up with it. I have attempted to use firefox developer edition as well as chrome dev tools

issue I am trying to debug:

```
<iframe>
   <html>
     <head>
       <script> javascript I want to debug </script>
     <body>
     </body>
   </html>
</iframe>

I would like to place breakpoints anywhere within the code to debug it.

```

Answer: 
In Chrome's devtools:

1. Open the **Sources** tab
2. Click the **Show Navigator** icon if the navigator isn't already showing

[![enter image description here](https://i.stack.imgur.com/MddLG.png)](https://i.stack.imgur.com/MddLG.png)
3. Find the name of the frame's HTML file in the navigator tree

[![enter image description here](https://i.stack.imgur.com/m3qMm.png)](https://i.stack.imgur.com/m3qMm.png)
4. Expand it, which will show the domain the frame is from, then expand it again to find frame's HTML file (again)

[![enter image description here](https://i.stack.imgur.com/BMlCr.png)](https://i.stack.imgur.com/BMlCr.png)
5. Click on that file to see its source

[![enter image description here](https://i.stack.imgur.com/ZcRKO.png)](https://i.stack.imgur.com/ZcRKO.png)
6. Within the script, click in the line number gutter to the right of the line where you want to set a breakpoint

[![enter image description here](https://i.stack.imgur.com/HssSu.png)](https://i.stack.imgur.com/HssSu.png)
Just a picture to visualize what Crowder wrote above. 
[![obove is the correct answer](https://i.stack.imgur.com/jSibP.jpg)](https://i.stack.imgur.com/jSibP.jpg)