Best way to check JavaScript object's value if object may be undefined-Record and share programming errors

I have a textarea that I have a blur event attached to. I don’t want the blur event to run if the user clicks on a specific span.dontClick on the page. However if the user clicks on anything other than the span.dontClick I do want the blur event to run. I have found a way to do this, but it looks awful, feels very hackey, and I’m guessing there is a better solution out there. Here’s what I’ve come up with:

if (event.type === 'focusout') {
  if (
    typeof event.originalEvent !== 'undefined' &&
    typeof event.originalEvent.currentTarget !== 'undefined' &&
    typeof event.originalEvent.currentTarget.activeElement !== 'undefined' &&
    typeof event.originalEvent.currentTarget.activeElement.className !== 'undefined' &&
    event.originalEvent.currentTarget.activeElement.className === 'dontClick'
  ) {
    // abort the code for the blur event (in effect, do nothing)
  }
  else {
    // run code for when a user blurs by not clicking on span
  }

It should probably be noted that the event object is from a jQuery event handler. I’m not sure if it is different or the same as the native event objects.

It should also be noted that this fails silently for most browsers but I get a debug window in IE if I don’t specify the ‘undefined’ state for each object all the way down the line…

If anyone has a more elegant solution I would really appreciate seeing it. Thanks!

1. You don’t need comparisons to undefined. Just do a truthy test. Also the test for the className isn’t needed. The === comparison will cover it.

    if (
       event.originalEvent &&
       event.originalEvent.currentTarget &&
       event.originalEvent.currentTarget.activeElement &&
       event.originalEvent.currentTarget.activeElement.className === 'dontClick'
     ) {
   

   but then you’re doing more work than needed anyway since jQuery gives you a reliable currentTarget.

    if (
       event.currentTarget.activeElement &&
       event.currentTarget.activeElement.className === 'dontClick'
     ) {
   

   or if you’re in a handler, just use this.

    if (this.activeElement && this.activeElement.className === 'dontClick') {
   

Originally posted 2013-08-31 05:11:48.