To find key in array for Javascript.

**Austinage** · 31-07-2009

Hello,

I want to know that how can I make an associative array in javascript? & How to find its length.
Can anyone please help me how to get javascript array key?

Thanks in advance.

**Darth** · 31-07-2009

Check if key exists or not in a JavaScript array

There is no easy in-built function in JS to check if a given key exists or not in a JavaScript array object.
The below small snippet works just fine:

Code:

<script type="text/javascript">
//lets setup a sample array and its key-and-values
var array=new Array();
array['name']='Rohan Shenoy';
array['gender']='Male';
array['age']='21';
 
//lets try to find an key which exists
if(array['name']==undefined)
{alert('That key is undefined');}
else
{alert('That keys exists');}
 
//lets try to find an key which does NOT exist
if(array['residence']==undefined)
{alert('That key is undefined');}
else
{alert('That keys exists');}
</script>

**GunPoint** · 31-07-2009

JavaScript Array get key

Code:

<html>
    <head>
        <h1>JavaScript Array get key</h1>    
        <title>JavaScript Array get key</title>
    </head>
    <body>
        <script language="javascript" type="text/javascript">
            array = {"W" : "WE", "L" : "LOVE","I":"INDIA" };
            for (key in array)
                document.write("For the Element " + "<b>"+array[key]+"</b>" 
                + " Key value is  " +"<b>"+key+"</b>"+"<br>");            
        </script>
        
    </body>
</html>