Note: Things listed at the start may not be very useful but things at the end are really magical.1.HTML Editor: [www.online-html-editor.de] This is full WYSIWYG editor, just type format and get the html code immediately.
2.CSS Editor: [CSSMate] This is one of the nice CSS tool, you can change font, background,layout and get CSS code on the fly.
3.HTML Code Cleaner: [DirtyMarkup] This is, one of the must have tool. You can clean your HTML code. It helps you in removing empty paragraph and sort of things. Just visit and have a look.
4.Quick Layout Maker: [YUI: CSS Grid Builder] I love this tool a lot. This is a quick way to get a blank layout of a webpage via YUI CSS. Best way to create a browser neutral layout.
5. jQuery Function Builder: [jQuery Builder]If you choosing to use jQuery for your webpage/mash-up then use this tool to quickly come up with the function layout. This is Good because we often forget the syntax and notations.
6.Chart Generator: [Google Chart Builder]Use this one to get a quick Google chart. Nice one.
7.Regular Expression builder: [http://txt2re.com/] OMG This is awesome tool, just brilliant. Use this to quickly build a regular expression in any language. This is not only specific for web developer. This is great online tool of all developers, no matter which language you working in. I love this because,I often work with different languages and I really hate to know that every language has different regular expression syntax.
8.YQL Console: [YQL Console] YQL is something which you find little weird at first, but once you know the power of it, you will be amazed. This is great way to create Mash-Up.
Here you type a SQL like syntax, which will be converted in to a URL, (REST URL) . This URL will fetch you data in the format you have selected (RSS/JSON/XML etc.) . You can get any data like search result from web, image. Or anything like images from flickr on even something like a very specific data from any URL. Please don't miss the HTML data source, because this can fetch you data from anywhere, using XPATH this is so powerful feature. Just enough tool to re-engineer entire web.
11.Image Compress: Smush.it™ This is really good tool, I don't know what it does, but i will compress your image well beyond your typical editor is compressing. Try it once. Good to save bandwidth.
13.Google API Playground: [AJAX APIs Playground] This is collection of working sample code which is using Google's Ajax APIs, nice and fancy way to quickly create a MashUp.
So that’s it. Enjoy creating Mash-Ups & Hack.. Online.
Tip: Bookmark this BlogPost to launch these tools anywhere.