object detection - document.getElementById

What to use when, what is the difference??



if(typeof document.getElementById == 'undefined') { return; }


if(!document.getElementById) return;

there is no difference AFAIK. the latter is shorter and therefore uses less bandwidth.

The result is the same, but the difference is type coercion during evaluation due to loose typing.

both could be used for object detection ??

The result is the same, but the difference is type coercion during evaluation due to loose typing.

difference is type coercion??:

eg [found an example -->]For example, the value 0.5 is coercible to the type "32 bit floating point number" but not to the type "32 bit signed integer".

what is meant during evaluation - the javascript parser parsing the script??

loose typing --> have an example ??

slow down ;)

Here's an explanation (under the heading Coercion):
http://msdn.microsoft.com/library/en-us/script56/html/js56jscondeclare.asp

Yeah, both can be used: each is an expression which produces the same result of evaluation (true or false). Which one to use is just a matter of preference.