Input validation should happen as early as possible in the data flow, preferably as soon as the data is received from the external party.
Data from all potentially untrusted sources should be subject to input validation, including not only Internet-facing web clients but also backend feeds over extranets, from suppliers, partners, vendors or regulators, each of which may be compromised on their own and start sending malformed data.
Syntactic validation should enforce correct syntax of structured fields (e.g.
SSN, date, currency symbol) while semantic validation should enforce correctness of their values in the specific business context (e.g.
Once open, the tools exist in their own window, each one connected to a single tab in Internet Explorer.
The website lets you check ownership of a website and find out what other sites link to it.
Students explore popular information sites and determine their validity as research sources.
For 5 different sources, they identify the author of an article and discuss whether it is a valid source to cite in research.
For F12 tools in Windows Internet Explorer 9 see How to use F12 Developer Tools to Debug your Webpages.
Great tools play a critical role in developer productivity, and while many web development tools exist, they likely don't meet your needs in all tasks.