Walkthrough of JavaScript IndexOf Method (calculates where the specified character first appears in the string) _ Basics

JavaScript IndexOf method

The IndexOf method computes the first occurrence of a specified string in a string and returns that value. The syntax is as follows:

Copy Code code as follows:

Str_object.indexof (search, start)

Parameter description:

Parameters	Description
Str_object	The string to manipulate (object)
Search	Necessary. The string to retrieve
Start	Optional. Specifies the location at which to start retrieving, such as omitting the argument, and starting from the first character of the string

Tip: The string is counted starting from 0.

IndexOf Method Instance

Copy Code code as follows:

<script language= "JavaScript" >

var str = "Www.jb51.net";
document.write (Str.indexof ("."));

</script>

Run the example and output:

Copy Code code as follows:

3

IndexOf is case-sensitive, and if the string value to retrieve does not appear, the method returns-1.