1...9 Properties

Summary

Return the nine most-recently memorized portions found during pattern matching. Read-only.

Syntax

RegExp.$ n

'RegExp’

Always the global RegExp object.

n

Any integer from 1 through 9.

Examples

The following example performs a regular expression search. It displays matches and submatches from the global RegExp object. The submatches are successful parenthesized matches that are contained in the … properties. The example also displays matches and submatches from the array that is returned by the exec method.

var newLine = "<br />";

 var re = /(\w+)@(\w+)\.(\w+)/g
 var src = "Please send mail to george@contoso.com and someone@example.com. Thanks!"

 var result;
 var s = "";

 // Get the first match.
 result = re.exec(src);

 while (result != null) {
     // Show the entire match.
     s += newLine;

     // Show the match and submatches from the RegExp global object.
     s += "RegExp.lastMatch: " + RegExp.lastMatch + newLine;
     s += "RegExp.: " + RegExp. + newLine;
     s += "RegExp.: " + RegExp. + newLine;
     s += "RegExp.: " + RegExp. + newLine;

     // Show the match and submatches from the array that is returned
     // by the exec method.
     for (var index = 0; index < result.length; index++) {
         s +=  index + ": ";
         s += result[index];
         s += newLine;
     }

     // Get the next match.
     result = re.exec(src);
 }
 document.write(s);

 // Output:
 //  RegExp.lastMatch: george@contoso.com
 //  RegExp.: george
 //  RegExp.: contoso
 //  RegExp.: com
 //  0: george@contoso.com
 //  1: george
 //  2: contoso
 //  3: com

 //  RegExp.lastMatch: someone@example.com
 //  RegExp.: someone
 //  RegExp.: example
 //  RegExp.: com
 //  0: someone@example.com
 //  1: someone
 //  2: example
 //  3: com

Remarks

The values of the $1…$9 properties are modified whenever a successful parenthesized match is made. Any number of parenthesized substrings may be specified in a regular expression pattern, but only the nine most recent can be stored.

Attributions

• Microsoft Developer Network: Article