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How to check if ID exists in html page

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  #1  
Old February 22nd, 2007, 12:10 PM
Damien-uk Damien-uk is offline
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How to check if ID exists in html page
Hi,

I'm doing some fairly basic client-side JS and wondered if there's a simple way to do something like:
Code:
if(getElementByID("someId"))
  //do something

At the moment I have some JS that I'm trying to re-use in a couple of places, but the IDs I'm operating on are different in each place.

I reckon there's probably a more elegant way that I could re-write the whole thing, but at this stage I don't have time for that...

I'm looking to avoid the JS errors that are occuring when my getElementByID() statements are executed on IDs not present on that particular page.

Any ideas?
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Old February 22nd, 2007, 12:11 PM
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huyaroo huyaroo is offline
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Use try and catch:

http://www.w3schools.com/js/js_try_catch.asp

Code:

try
{
// do whatever you want with your getElementById here
}
catch(err)
{
// id does exist
}
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Last edited by huyaroo : February 22nd, 2007 at 12:14 PM.
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Old February 22nd, 2007, 12:28 PM
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Quote:
Originally Posted by Damien-uk
I'm doing some fairly basic client-side JS and wondered if there's a simple way to do something like:
Code:
if(getElementByID("someId"))
  //do something


The code you provided is the most elegant way of checking for element with specified ID.

That way you can see that code depends on a presence of a certain ID in the document, while try ... catch will catch all errors, even those that are not related to missing IDs.

I would recommend sticking with your code, it's elegant and good coding style.
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Old February 22nd, 2007, 02:25 PM
Damien-uk Damien-uk is offline
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Thanks to both of you - I wasn't aware of (or I think in fact had forgotten about) try / catch in JS!

That's a nice easy solution to that one then... cheers!
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