All too often I've seen folks bang their heads against a wall trying to figure out why their HTML or CSS code isn't working correctly. I've done it myself at times. When we find the reason, it's usually a silly typo we made somewhere in the code that's the culprit.

While many code editing software like Dreamweaver has spellchecking as part of its process, it doesn't always catch things like misspellings within path names such as ".../images/freind/" for example.

I use the free code editor Notepad++ which has a great plugin called compare. This allows you to bring up two codes side by side and shows you exactly where there is a difference. This is very useful if you have some code that was previously working and you made changes to it but it no longer works properly. It highlights the changes you made to quickly find the problem. I use it for HTML, CSS and javascript/jQuery code as well.

What other solutions does everyone use to quickly check your code for errors?

Code completion in Visual Studio (with ReSharper) quickly identifies undefined classes or paths to missing files (usually typos) and more. At home I also use PhpStorm which offers similar functionality.

No matter how nice text editors can be, I can't imagine coding without a decent IDE.