indexOf is not working in javascript OR searching a item in a list OR searching a item in array in javascript

indexOf is not working in javascript.

//code :  // not wotking

var commonerr = [ 1, 2, 3, 4, 5 , 6 ];     //array              

if (commonerr.indexOf(errorNumber)  != -1){   

// to do 

}

IndexOf is not supported in Internet explorer. Its supported in FF and other browsers.

I found few blogs and its seems like they have a work around for this. You can simply use prototype to extend this method.  please refer below url.
http://www.pearweb.com/javascript/array-index-of.html

2nd way :

Or you can use below code. Jquery has a nice method "inArray" which will help you in searching a item in a array.

here is the link of jquery
http://api.jquery.com/jQuery.inArray/

var commonerr = [ 1, 2, 3, 4, 5 , 6 ];     //array                      
                            

if ( $.inArray(errorNumber, commonerr) != -1){  

//to do

}