Returns the characters from the beginning of a searched string up to the position before the beginning of the last match. Read-only.

RegExp.leftContext

The object associated with this property is always the global RegExp object.

Remarks

The initial value of the leftContext property is an empty string. The value of the leftContext property changes whenever a successful match is made.

Example

The following example illustrates the use of the leftContext property:

function matchDemo(){
   var s;                                //Declare variable.
   var re = new RegExp("d(b+)(d)","ig"); //Regular expression pattern.
   var str = "cdbBdbsbdbdz";             //String to be searched.
   var arr = re.exec(str);               //Perform the search.
   s = "$1 returns: " + RegExp.$1 + "\n";
   s += "$2 returns: " + RegExp.$2 + "\n";
   s += "$3 returns: " + RegExp.$3 + "\n";
   s += "input returns : " + RegExp.input + "\n";
   s += "lastMatch returns: " + RegExp.lastMatch + "\n";
   s += "leftContext returns: " + RegExp.leftContext + "\n";
   s += "rightContext returns: " + RegExp.rightContext + "\n"; 
   s += "lastParen returns: " + RegExp.lastParen + "\n";
   return(s);                            //Return results.
}
document.write(matchDemo());

Requirements

Version 5.5

See Also

$1...$9 Properties | index Property | input Property | lastIndex Property | lastMatch Property | lastParen Property | rightContext Property

Applies To: RegExp Object