This method returns the index within the calling String object of the last occurrence of the specified value, starting the search at fromIndex or -1 if the value is not found.
Its syntax is as follows −
string.lastIndexOf(searchValue[, fromIndex])
searchValue − A string representing the value to search for.
fromIndex − The location within the calling string to start the search from. It can be any integer between 0 and the length of the string. The default value is 0.
Returns the index of the last found occurrence, otherwise -1 if not found.
Try the following example.
<html> <head> <title>JavaScript String lastIndexOf() Method</title> </head> <body> <script type="text/javascript"> var str1 = new String( "This is string one and again string" ); var index = str1.lastIndexOf( "string" ); document.write("lastIndexOf found String :" + index ); document.write("<br />"); var index = str1.lastIndexOf( "one" ); document.write("lastIndexOf found String :" + index ); </script> </body> </html>
lastIndexOf found String :29 lastIndexOf found String :15