Regular Expressions and Pattern Matching - JavaScript by Example - page 748

EXAMPLE 17.19 ( CONTINUED )

1 var reg_expression = /[A-Z][a-z]*\s/;

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 /[A-Z][a-z]*\\s/
matched the string"+ textString +"\".<br />");

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

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

EXPLANATION
1 The variable is assigned a regular expression containing an uppercase letter, [A-

Z] , followed by zero or more lowercase letters, [a-z]* , and a space, \s . There are
either zero or more lowercase letters.

2 The variable textString is assigned user input; in this example, Danny boy was en-

tered.

3 The regular expression test method will return true because the string Danny boy

matches an uppercase letter D , followed by zero or more lowercase letters anny ,
and a space. See Figure 17.21.

Figure 17.21 The user entered Danny boy , consisting of one uppercase letter, zero
or more lowercase letters, and a space (top); the user entered DANNY BOY ,
consisting one uppercase letter, zero lowercase letters, and a space (bottom).
Note: the “Y” is followed by a space.