Easiest way to mask characters in HTML(5) text input
Look up the new HTML5 Input Types. These instruct browsers to perform client-side filtering of data, but the implementation is incomplete across different browsers. The pattern attribute will do regex-style filtering, but, again, browsers don't fully (or at all) support it.
However, these won't block the input itself, it will simply prevent submitting the form with the invalid data. You'll still need to trap the onkeydown event to block key input before it displays on the screen.
Basic validation can be performed by choosing the type attribute of input elements. For example:
<input type="email" /> <input type="URL" /> <input type="number" />using pattern attribute like:
<input type="text" pattern="[1-4]{5}" />required attribute
<input type="text" required />maxlength:
<input type="text" maxlength="20" />min & max:
<input type="number" min="1" max="4" />
Yes, according to HTML5 drafts you can use the pattern attribute to specify the allowed input using a regular expression. For some types of data, you can use special input fields like <input type=email>. But these features still widely lack support or have qualitatively poor support.