JavaScript lastIndexOf method entry example (calculates the last occurrence of a specified character in a string)

JavaScript lastIndexOf method

The lastIndexOf method calculates the last occurrence of the specified string in the entire string and returns the value. The syntax is as follows:

str_object.lastIndexOf( search, start )

Parameter description:

parameter	instructions
str_object	String (object) to manipulate
search	A necessity. The string to retrieve
start	Optional. Specifies where to start the retrieval, and if the parameter is omitted, the retrieval begins with the last character of the string

Tip: strings are counted from 0.

Example of the lastIndexOf method

<script language="JavaScript">
var str = "www.jb51.net";

document.write( str.lastIndexOf( "." ) + "<br />" );

document.write( str.lastIndexOf( ".", 5 ) + "<br />" );

document.write( str.lastIndexOf( ".", 10 ) );
</script>

Run the example and output:

9

3

9

Note that in the example above where the second argument is 5, what is actually found is the first. Symbol, which is a search in the www.5 string.
LastIndexOf is case-sensitive and returns -1 if the string value to be retrieved does not appear.