Search and Destroy - JavaScript

The previous set of examples highlighted the search capabilities of the String object. But that's not all! You can also perform a search-and-replace operation with the replace() method, which accepts both a regular expression and the value to replace it with. Here's how:


<script language="JavaScript">
 
// set string
var str = "Welcome to the Matrix, Mr. Anderson";
 
// uncomment to check initial value
// alert(str);
 
// replace a string with another string
// The One turns into Smith
str 
= str.replace(/Anderson/,"Smith");
 
// display new string
alert(str)
 
</script>



If you load this example in a browser, you will see that the string "Anderson" has been replaced with the string "Smith". The following output illustrates:

Welcome to the Matrix, Mr. Smith

Remember how I used the "g" modifier to search for multiple instances of a pattern within a string? Take it one step further - you can even use it to replace multiple instances of a pattern within the string:


<script language="JavaScript">
 
// set string
var str = "yo ho ho and a bottle of gum";
 
// returns "yoo hoo hoo and a bottle of gum"
alert(str.replace(/os/g, "oo 
"));
 
</script> 



Here, the \s metacharacter matches the space after "yo" and "ho" and replaces with "oo".

You can also use case-insensitive pattern matching - simply add the "i" modifier (for "insensitive") at the end of the pattern. The next example shows you how:


<script language="JavaScript">
 
// set string
var str = "he He hE HE";
 
// returns ho ho ho ho
alert(str.replace(/he/gi, "ho"));
 
</script>