↑
Main Page

RegExp.multiline

You can also use the short names for these properties, although you must use the bracket notation for

most of them because some names use illegal ECMAScript syntax:

var sToMatch = “this has been a short, short summer”;

var reShort = /(s)hort/g;

reShort.test(sToMatch);

alert(RegExp.$_); //outputs “this has been a short, short summer”

alert(RegExp[“$`”]); //outputs “this has been a “

alert(RegExp[“$’”]); //outputs “, short summer”

alert(RegExp[“$&”]); //outputs “short”

alert(RegExp[“$+”]); //outputs “s”

Keep in mind that every time

exec()

test()

is called, all these properties (except

multiline

) are

reset. Example:

var sToMatch1 = “this has been a short, short summer”;

var sToMatch2 = “this has been a long, long summer”;

var reShort = /(s)hort/g;

var reLong = /(l)ong/g;

reShort.test(sToMatch1);

alert(RegExp.$_); //outputs “this has been a short, short summer”

alert(RegExp[“$`”]); //outputs “this has been a “

alert(RegExp[“$’”]); //outputs “, short summer”

alert(RegExp[“$&”]); //outputs “short”

alert(RegExp[“$+”]); //outputs “s”

reLong.test(sToMatch1);

alert(RegExp.$_); //outputs “this has been a long, long summer”

alert(RegExp[“$`”]); //outputs “this has been a “

alert(RegExp[“$’”]); //outputs “, long summer”

alert(RegExp[“$&”]); //outputs “long”

alert(RegExp[“$+”]); //outputs “l”

Here, a second regular expression,

reLong

, is used after

reShort

. All the

RegExp

properties are set to

new values.

The

multiline

property is a different type of property because it doesn’t depend on the last executed

match. Instead, it sets the

option for every regular expression in scope:

var sToMatch = “First second\nthird fourth\nfifth sixth”

var reLastWordOnLine = /(\w+)$/g;

RegExp.multiline = true;

var arrWords = sToMatch.match(reLastWordOnLine);

When this code completes execution,

arrWords

contains

“second”

“fourth”

, and

“sixth”

, just as if

the

option is used in the regular expression.

Internet Explorer and Opera don’t support

RegExp.multiline

, so it’s best to use the

setting on individual expressions instead of trying to set this flag globally.

215

Regular Expressions

10_579088 ch07.qxd 3/28/05 11:38 AM Page 215