From Overview of JavaScript I -- Basic Web Scripting Language CPS616 Technologies of the Information Age -- Spring Semester 99. byGeoffrey C. Fox (Tom Scavo)
Here are two examples: function isDigit( str ) { var regexp = /^[0-9]*$/; return regexp.test( str ); } function isSSN( str ) { // match 999999999 or 999-99-9999 var regexp = /^(\d{9}|\d{3}-\d{2}-\d{4})$/; return regexp.test( str ); }