lastIndexOf Method (String) (JavaScript)

Returns the last occurrence of a substring within a String object.

strObj.lastIndexOf(substring[, startindex])


Required. A String object or literal.


Required. The substring to search for within the String object.


Optional. Integer value specifying the index to begin searching within the String object. If omitted, searching begins at the end of the string.

The lastIndexOf method returns an integer value indicating the beginning of the substring within the String object. If the substring is not found, a -1 is returned.

If startindex is negative, startindex is treated as zero. If it is larger than the greatest character position index, it is treated as the largest possible index.

Searching is performed right to left. Otherwise, this method is identical to indexOf.

The following example illustrates the use of the lastIndexOf method.

var str = "time, time";

var s = "";
s += "time is at position " + str.lastIndexOf("time");
s += "<br />";
s += "abc is at position " + str.lastIndexOf("abc");


// Output:
//   time is at position 6
//   abc is at position -1

Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards. See Version Information.

Applies To: String Object (JavaScript)