How do I check if an object has properties

[erikcw]

Hi,

I'm working on a script that performs some operations on a page element with an id='example1'.

The problem is, it's an ajax page, and that element is not always there. So if it isn't on the page when the javascript runs, I get an error saying:

$(chkTracker[i][0]) has no properties

How can I check if that object does infact have properties? (something like php's is_set?)

Thanks!
Erik

[Fotiman]

You can just include the object to check in the condition of an if statement. If the object is undefined, the condition will evaluate to false. For example:

<script type="text/javascript"> 
var realObj = { 
 "foo":"bar" 
}; 
if( realObj ) 
{ 
 alert( "realObj exists and has foo property: " + realObj["foo"] ); 
 if( realObj["xyz"] ) 
 { 
  // This will not happen 
  alert( "realObj has xyz" ); 
 } 
 else 
 { 
  alert( "realObj does not have xyz property" ); 
 } 
} 
</script>