SYTYAWD #4 Using Regular Expressions In Java Script

Regular Expressions in Java Script

One you have the Regular Expression syntax down working with it inside of Java Script is a breeze.

Inside of Java Script Regular Expression can be created in two ways. As literals or by calling the constructor of the RegExp object. In most cases I prefer calling the constructor, because I find it makes the code more readable.

As a literal:

var re = //bjeff/b/;

Calling the constructor:

var re = new RegExp(“/bjeff/b”);

Perform a search on a string, and then write the results to the page.

var printArray = function (x) {document.writeln(x + "<br>");}
var stringToSearch = "dood this is soo cool";
var re = new RegExp ("d(o+)d", "g");		// return any o’s that are between d and the full word
var matches = re.exec(stringToSearch);

matches.forEach(printArray);

Perform a string substitution, and then write the results to the page

       var stringToSearch ="dood this is soo cool, doooooood";
      	var re = new RegExp("/dood/g");
      	var processedString = stringToSearch.replace(/dood/g, "dude");	// replace the full word dood w/ dude

      	document.writeln(processedString);

The Java Script RegExp object has the following methods that are useful.

Tip #1 Use Regular Expressions For Client Side Validation

Wire your onBlur or keyPress event to call a function that runs a Regular Expression on the content of the control. Below you will find a bunch Regular Expressions for common validation needs.

Tip # 2 Tools For Regular Expressions in Java Script

• Regular Expression.info
• Expresso