jquery - Can't set element ID in JavaScript, it's always undefined -

i want have function generates id's on fly given jquery object, if doesn't have 1 already. these id's should used in future requests.

i came code below, doesn't work. id's never set. commented out alert statement below return undefined.

i pass code $(this) or $(options.el) parameter substitute 'el'. initially, elements not have explicitly id set in html.

any appreciated, here's code:

getelementid: function(el)  {    if(undefined == el.attr('id'))    {       el.attr('id',"anim-"+math.random().tostring().substr(2));    }    // alert(el.attr('id'));    return el.attr('id'); }, 

try changing:

if(undefined == el.attr('id'))

to:

if("" == el.attr('id'))