Array search from start with indexOf()

In this chapter you will learn:

How to search an Javascript array from start

Array indexOf()

Its syntax:

indexOf(itemToLookFor, optionalIndexToStartWith)

indexOf() starts searching from the front of the array. indexOf() returns the position of the item in the array or -1 if the item isn't in the array.

An identity comparison is used during comparing.

<!DOCTYPE html><!-- j a  va2s  .  c  o m-->
<html>
<head>
    <script type="text/javascript">
        var numbers = [1,2,3,4,5,4,3,2,1]; 
        document.writeln(numbers.indexOf(4)); //3 
        document.writeln(numbers.indexOf(4, 4)); //5 
        
        var person = { name: "JavaScript" }; 
        var people = [{ name: "JavaScript" }]; 
        
        var morePeople = [person]; 
        document.writeln(people.indexOf(person)); //-1 
       
    </script>
</head>
<body>
</body>
</html>

Click to view the demo

Next chapter...

What you will learn in the next chapter:

How to search a Javascript array from the end

Array search from start with indexOf()

Array indexOf()

Next chapter...

Array Type

Array creation

Array type detecting

Array iterate

Array Length

Add to Array

Array join

Array concat()

Array every method

Array search from start with indexOf()

Array search from the end with lastIndexOf()

Array filter

Array mapping

Array forEach

Array pop and push

Array shift()

Array reduce()

Array reduceRight()

Array reverse()

Array slice()

Array some()

Array splice()

Array sort()

Array toString()

Array unshift()