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JavaScript String indexOf() Method
What is JavaScript String indexOf() Method
JavaScript indexOf() method is used to find the position of the first occurrence of some specified value in a given input string. It returns -1 value if the value to search for never occurs in the given input string.
Syntax:
string.indexOf(searchvalue, start)
Parameter Values
| Parameter | Description |
|---|---|
| searchvalue | This is a required parameter. It defines the string to search for. |
| start | This is an optional parameter. It defines at which position to start the search. |
Browser Support
| Method | Chrome | Edge | Firefox | Safari | Opera |
|---|---|---|---|---|---|
| indexOf() | Yes | Yes | Yes | Yes | Yes |
Here is an example of indexOf() method:
<html>
<body>
<p>Click the button to see the Output</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
var str = "Welcome to PHPTPOINT";
var n = str.indexOf("PHP");
document.getElementById("demo").innerHTML = n;
}
</script>
</body>
</html>
Output:
Click the button to see the Output
Example 2:
<html>
<body>
<p>Click the button to see the Output</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
var str = "Welcome to PHPTPOINT";
var n = str.indexOf("T");
document.getElementById("demo").innerHTML = n;
}
</script>
</body>
</html>
Output:
Click the button to see the Output
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