Javascript dynamic element Id

Question

I am trying to pass an element through my function and output the id.

Here is what I mean:

<input id='password' style="display:inline-block" type="password" name='Password' onKeyDown="setTimeout('validate(this)', 10)" />

and the javascript:

var validate = function(element)
{
    alert(element.id);        
}

Is this the correct way to do the following? All I get is undefined when it alerts. Thank you.

You shouldn't use a string as the first argument from setTimeout() because it is the same as using eval. — Saxoier
– Saxoier, Commented Jul 11, 2011 at 0:38

The Scrum Meister · Accepted Answer · 2011-07-11 00:35:48Z

4

When called from the setTimeout function, the this pointer is no longer pointing to the input element, rather it is pointing to the window object.

What you can do is

onKeyDown="var self=this;setTimeout(function(){validate(self);}, 10)"

Or better yet:

var validateFn = function(element) {
    return function(){
        alert(element.id);
    };
}

and on the element:

onKeyDown="setTimeout(validateFn(this), 10)"

answered Jul 11, 2011 at 0:35

The Scrum Meister

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1 Comment

grep Over a year ago

Perfect! Ha, I thought I was going crazy.

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