I was using the Firefox 3.6.16 web browser and it got really slow. Â Unbearably so.
When I went to look at the console, it was filled with all kinds detailed of JavaScript warnings, the kind one might expect out of JSLint. Â It was spending so much time checking the JavaScript code that it was barely spending time executing it.
The “culprit” was the Web Developer add-on.
Normally, the Disable / Disable JavaScript / Strict Warnings menu item is checked. Â Unchecking it gives some fantastic diagnostic messages when writing code. Â Forget to re-check it and regular web usage may come to a crawl.
Aside from the console being a clue, you may also see a caution sign or a red circle with a white ‘x’ in it on the Web Developer toolbar.
For normal speeds when regularly browsing, just disable strict checking.
