jQuery – existing of document parent-Collection of common programming errors

Found a few similar articles, but can’t seem to get anything to work.

We have this code as follows:

parent.$("#toTop").trigger("click");

However, we need to check for the existence of the parent element as it is throwing an error in some cases where dom setup is different:

parent.$(...) is null

How would I do that?

1. Try something like

   if(parent.$("#toTop")){//Not true if is undefined / null 
   //codes
   }
   

   It is probably safer to use

   if(parent.$("#toTop").length)){
       //codes
       }
   

2. if( parent && parent.$("#toTop")) {
       parent.$("#toTop").trigger("click");
   }
   

   If you are specifically looking only for the parent you can use this

   if( parent )
   

   There might be a case when the parent gives you a empty selector. So you can check for the length in such cases..

   if(parent.length) 
   

Originally posted 2013-11-09 19:43:08.