You can send a form for validation prior to submitting it by
adding the JavaScript onSubmit
method to the <form> tag.
Make sure that your function returns true if the form is to be submitted and
false otherwise.
To match a string against a regular expression in JavaScript,
use the test method.
Regular expressions to match characters not in a word could be
any of /[^\w]/, /[\W]/, /[^a-zA-Z0-9_]/, and so on.
A regular expression to match either of the words “fox” or “fix”
could be /f[oi]x/.
A regular expression to match any single word followed by any
nonword character could be /\w+\W/g.
A JavaScript function using regular expressions to test whether the word “fox” exists in the string “The quick brown fox” could be:
document.write(/fox/.test("The quick brown fox"))A PHP function using a regular expression to replace all occurrences of the word “the” in “The cow jumps over the moon” with the word “my” could be:
$s=preg_replace("/the/i", "my", "The cow jumps over the moon");The HTML keyword used to precomplete form fields with a value is
the value keyword, which is placed
within an <input> tag and
takes the form value="value".