JavaScript Examples Bible - UserWorks Technologies

474
JavaScript Examples Bible: The Essential Companion to JavaScript Bible
stringObject.match()
string.lastIndexOf(searchString[,
startIndex])
NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5
Compatibility ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Example
Enter each of the following statements (up to, but not including the “//” comment
symbols) into the top text box of The Evaluator (you can simply replace the parameters
of the lastIndexOf() method for each statement after the first one).
Compare your results with the results shown below.
a = “bananas”
a.lastIndexOf(“b”) // result = 0 (index of 1st letter is zero)
a.lastIndexOf(“a”) // result = 5
a.lastIndexOf(“a”,1) // result = 1 (from 2nd letter toward the front)
a.lastIndexOf(“a”,2) // result = 1 (start from 3rd letter working toward front)
a.lastIndexOf(“a”,4) // result = 3 (start from 5th letter)
a.lastIndexOf(“nan”) // result = 2 [except for -1 Nav 2.0 bug]
a.lastIndexOf(“nas”) // result = 4
a.lastIndexOf(“s”) // result = 6
a.lastIndexOf(“z”) // result = -1 (no “z” in string)
string.match(regExpression)
NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5
Compatibility ✓ ✓ ✓ ✓ ✓
Example
To help you understand the string.match() method, Listing 34-3 provides a
workshop area for experimentation. Two fields occur for data entry: the first is for
the long string to be examined by the method; the second is for a regular expression.
Some default values are provided in case you’re not yet familiar with the syntax
of regular expressions (see Chapter 38 of the JavaScript Bible). A check box lets
you specify whether the search through the string for matches should be casesensitive.
After you click the “Execute match( )” button, the script creates a regular
expression object out of your input, performs the string.match() method on the
big string, and reports two kinds of results to the page. The primary result is a
string version of the array returned by the method; the other is a count of items
returned.