is there an equivalent 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
}

Answer 3

http://phpjs.org/functions/array_key_exists:323

This is a great site for PHP programmers moving to js.