Jquery if div doesn't exist

I'm using 1 js for 2 different pages. 1 page doesn't have a div which the开发者_如何转开发 other does. So when I submit the values, I get a $( js error

for

$('.description'+save_id+'').html(description_val).show(); //update category description

I suspect that I get the error because there is nothing to show(). Is there a short code I can use to detect if the div.description exists otherwise don't do the function?

jQuery will not error if it has nothing to perform on. The show() would not be a problem. To answer your question, though, you can check the length property on the jQuery object returned from $.

If the description_val variable is undefined, then the code will fail.

Try using an if() statement to only run the code if description_val is not undefined.

if(description_val) {
    $('.description'+save_id+'').html(description_val).show();
}

Or if for some reason the value of description_val may be a value that would equate to false, then do this:

if(description_val !== undefined) {
    $('.description'+save_id+'').html(description_val).show();
}

From what you posted I'd check to make sure the variables you're using are all defined at this stage. To check for existence you can do this:

if ($('.description' + save_id).size() > 0) {
  // code here that operates on the div.
}

This is essentially just a syntactic alternative to checking the length property.