Web Programming Step by Step

Lecture XX
Client-Side Validation

Except where otherwise noted, the contents of this presentation are Copyright 2010 Marty Stepp and Jessica Miller.

Valid XHTML 1.1

Valid CSS!

Regular expressions in JavaScript

string.match(regex)
- if string fits the pattern, returns the matching text; else returns null
- can be used as a Boolean truthy/falsey test:
  var name = $("name").value; if (name.match(/[a-z]+/)) { ... }
an i can be placed after the regex for a case-insensitive match
- name.match(/Marty/i) will match "marty", "MaRtY", ...

Replacing text with regular expressions

string.replace(regex, "text")
- replaces the first occurrence of given pattern with the given text
- var str = "Marty Stepp";
  str.replace(/[a-z]/, "x") returns "Mxrty Stepp"
- returns the modified string as its result; must be stored
  str = str.replace(/[a-z]/, "x")
a g can be placed after the regex for a global match (replace all occurrences)
- str.replace(/[a-z]/g, "x") returns "Mxxxx Sxxxx"


					using a regex as a filter
						
							str = str.replace(/[^A-Z]+/g, "") turns str into "MS"