is there an equalant to PHP array_key_exists in javascript or jquery [duplicate]

Question

Possible Duplicate:
Checking if an associative array key exists in Javascript

I have a PHP code block . For a purpose I am converting this to a JavaScript block.

I have PHP

if(array_key_exists($val['preferenceIDTmp'], $selected_pref_array[1])) 

now I want to do this in jQuery. Is there any built in function to do this?

Answer 1

Note that objects (with named properties) and associative arrays are the same thing in javascript.

You can use hasOwnProperty to check if an object contains a given property:

o = new Object();   o.prop = 'exists'; // or o['prop'] = 'exists', this is equivalent   function changeO() {     o.newprop = o.prop;     delete o.prop;   }    o.hasOwnProperty('prop');   //returns true   changeO();   o.hasOwnProperty('prop');   //returns false   

Alternatively, you can use:

if (prop in object) 

The subtle difference is that the latter checks the prototype chain.

Answer 2

In Javascript....

if(nameofarray['preferenceIDTmp'] != undefined) {     // It exists } else {     // Does not exist }