AutoCopy
AutoCopy instructs Firefox to copy text when it’s highlighted. Very helpful when copying content from a customer’s old site into their new one.
ColorZilla
ColorZilla lets me place my cursor over anything on the page and it gives me the hex color of the pixel. It’s a huge time saver as it allows me the ability to avoid doing a print-screen, opening Photoshop, and using the Photoshop color dropper to get the color.
Firebug
Firebug is an absolute must for my Ajax / Javascript debugging. I couldn’t get by without it.
HTML Validator
HTML Validator just validates how great my code is.
Link Alert
Link Alert changes my cursor when I hover over a link. The cursor changes to a visual representation of what I’m about to click on. It’s great for me because it tells me if the link is to a javascript file, text file, or mp3 file. I love it. It also tells me if clicking on a link triggers a javascript event.
MeasureIt
MeasureIt gives me a ruler to mention object dimensions. This tool gives me a broad idea over how much space an object is taking up or how much space I have left to work with on my page.
Server Spy
Server Spy is dominant because I can instantly tell what type of server the current website is on. A must when trying to quote a new project.
Web Developer Toolbar
The WDT is as important to me as Firebug. WDT gives me a ton of control and information about the page I’m developing. Again, this is a must.
If you’re a Web developer, you likely already know about Firebug - the amazing web development add-in for Firefox. But if you haven’t been following its development blog, you may not know the latest news: Firebug 1.2 has moved from alpha to beta, and it’s ready for Firefox 3.
The new release isn’t just a version port; it’s also got substantial new functionality. This includes a good deal of performance work, better javascript debugging, and a redesigned console. if you’re doing any work in Firefox 3 it’s definitely worth grabbing.
Before uploading files via a HTML-form, I want to do some client-side validating.
E.g. to check the filesize of the file selected by the user to upload.
Filesize should be, say, between 5MB and 50 MB. Javascript solution?!?
Nope, not really. By design, a person’s browser isn’t allowed to snoop around the file system.