How do I preform JS code inside <script> tag in Google Chrome?

I am trying to debug JS code inside a tag <script>

. So I need to set some breakpoints, but I can't do that as Google Chrome doesn't prefix the code inside the tag <script>

. When I click on the "Prettify" button, the browser just warns the HTML and doesn't touch the JS. Mozilla Firefox also has the same problem. Is there a way to force the browser to disable the JS code?