One way to help you make web pages, that work across multiple browsers is to use an HTML validator, that can help you identify problems and quickly correct them.
So with all of the boring technical guff out of the way, let’s get on with the interesting technical guff and take a look at some examples of form validation.
One of the most common patterns of validation is that of mandatory (that is, required) values — the fields that the user must complete in order to progress.
As you fix your markup to remove one error, you may find that you generate more-- or that suddenly several other errors go away.
For example, if you add a missing end-table tag () represents data in two dimensions or more.") to a document, you might fix every "element not allowed here" error that followed.
One example is wrapping an inline element like element is a generic inline container for phrasing content, which does not inherently represent anything.
It can be used to group elements for styling purposes (using the class or id attributes), or because they share attribute values, such as lang.
Here are a few of the most common errors and pitfalls to avoid.
If you get an attribute-related error, it's very likely going to tell you that you forgot to include a required attribute.
Your goal is simple: to bring your page to a state where it doesn't generate any errors at all.