JavaScript indexOf () method

Definition and Usage

Definition and usage

The IndexOf () method returns the position of the the ' the ' of the ' the ' a specified string value in a string.

The IndexOf () method returns the position of the specified value at the first occurrence of the string

Syntax

GrammarstringObject.indexOf(searchvalue,fromindex)　

Parameter Parameters	Description Comments
Searchvalue The value that you want to match	Required. Specifies a string value to search for Required option. Specify the value you want to find a match for
Fromindex Starting position	Optional. Specifies where to start the search Options available. Match the start position

Tips and Notes

Attention

Note:the indexOf () method was case sensitive!

Note: the IndexOf () method is an exact match

Note:this method Returns-1 If the string value to search for never occurs.

Note: If no matching value is available, return-1 Example

Instance

In this example we'll do different searches within a "Hello world!" string:

In this case, we're going to "Hello world!" String for different lookup matches:

<script type="text/javascript">
var str="Hello world!"
document.write(str.indexOf("Hello") + "<br />")
document.write(str.indexOf("World") + "<br />")
document.write(str.indexOf("world"))
</script>　

The output of the code above would be:

The result returned is:

0
-1
6　

Try-it-yourself Demos

Interactive walkthroughs

IndexOf ()

IndexOf () to search within a string.

How to find and match a string with indexof ()