Regular Expressions and Pattern Matching - JavaScript by Example - page 755

EXAMPLE 17.26 ( CONTINUED )

<script type="text/javascript">

1 var reg_expression = /^Will/; // Beginning of line anchor

2 var textString=prompt("Type a string of text","");

3 var result=reg_expression.test(textString) ;// Returns true

// or false

document.write(result+"<br />");
if (result){
document.write("<b>The regular expression /^Will/ matched
the string\""+ textString +"\".<br />");

}
else{
alert("No Match!");

}
</script>
</body>
</html>

EXPLANATION
1

The variable is assigned a regular expression containing the beginning of line an-
chor metacharacter, the caret, followed by Will .

2 The variable textString is assigned user input; in this example, Willie Wonker was

entered.

3 The regular expression test() method will return true because the string Willie

Wonker begins with Will . See Figure 17.28.

Figure 17.28 The user entered Willie Wonker . Will is at the beginning of the line, so
this tests true (top); if the user enters I know Willie , and Will is not at the beginning of
the line, the input would test false (bottom).