Metacharacters, Flags and Regular Expressions in JavaScript

As I said in part two of the series, the m flag is not used in a straightforward manner. This is what you have in the specification about the m flag:

The m flag is used to match over multiple lines.

The m flag reflects whether or not to search in strings across multiple lines.

multiline is a property of an individual regular expression object..

The value of multiline is true if the "m" flag was used; otherwise, it is false. The "m" flag indicates that a multiline input string should be treated as multiple lines. For example, if "m" is used, "^" and "$" change from matching at only the start or end of the entire string to the start or end of any line within the string.

You cannot change this property directly.

In my opinion the specification is not clear. Well, I will not say any more about the g flag than what I have said in this section.

Combining Flags

There are three flags. You can combine them. The following code combines the i and m flags. Each test function produces a match.

<script type="text/javascript">

var availableString = "A dog is an animal. Dogs are domestic animals. There are different species of dogs";

var re = /dog/ig ;

if (re.test(availableString))

alert('Matched');

else

alert('Not Matched');

alert(re.lastIndex);

if (re.test(availableString))

alert('Matched');

else

alert('Not Matched');

alert(re.lastIndex);

</script> 

We have come to the end of this part of the series. We have also come to the end of the first phase of the series. In the next phase and last part of the series, we shall talk more about the properties and methods of the regexp object. We shall also talk about properties and methods of related string objects.

Let us take a break here, and continue in the next part.