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lastIndexOf Method (String) (JavaScript)

Returns the last occurrence of a substring in the string.

strObj.lastIndexOf(substring[, startindex])

strObj

Required. A String object or string literal.

substring

Required. The substring to search for.

startindex

Optional. The index at which to begin searching. If omitted, the search 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 starting at the last character in the string. 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");

document.write(s);

// 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, Internet Explorer 10 standards, Internet Explorer 11 standards. Also supported in Store apps (Windows 8 and Windows Phone 8.1). See Version Information.

Applies To: String Object (JavaScript)

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