The basic language constructs include character classes, quantifiers, and meta-characters. Match any character (except newline) $ Match the end of the line (or before newline at the end) | Alternation (‘or’ statement) () Grouping  Custom character class These two meta-characters are core parts of flexible regular expressions.Character classes are used to define the content of the pattern. For instance, in the first example we lost our wallet.Instead of as this lets the browser (and the user) know that the contents of that field need to be secured.The password won't appear on the screen as you type and most browsers also won't 'remember' the values entered in fields as they do with other form elements.If the purpose of registration is to confirm that the person exists, and that they have supplied a valid email address, then as part of the registration processe you a should either email them a random password or a confirmation token rather than letting them choose their own password and use it immediately.The code presented below would then be used for letting the user change their password.Because the input type obscures the text typed, you should let the user confirm that they haven't made a mistake.
These descriptions can then be used in nearly infinite ways. Dot, any character (may or may not match line terminators, read on) \d A digit: [0-9] \D A non-digit: [^0-9] \s A whitespace character: [ \t\n\x0B\f\r] \S A non-whitespace character: [^\s] \w A word character: [a-z A-Z_0-9] \W A non-word character: [^\w]\ Escape the next meta-character (it becomes a normal/literal character) ^ Match the beginning of the line .
This free regular expression tester lets you test your regular expressions against any entry of your choice and clearly highlights all matches.
It is Java Script based and uses XReg Exp library for enhanced features.
In some cases, such as on mobile devices, displaying the password may improve usability without compromising security.
After all it's only the browser display being obfuscated and not the data transfer.