empty jQuery string not empty

Question

Can someone please explain this to me? I am attempting to do something if key != ''

var key = "";
if($('div[title="Keyword"]').text() != '') {
  key = $('div[title="Keyword"]').text().trim(); 
}

//this always alerts
if (key != '') { alert(key); } 

//this never alerts
if (!key) { alert(key); }

alert the value of key before the if and see what is it equal to. If it's not an empty string, then the first if will pass. — David G
– David G, Commented Oct 4, 2012 at 0:15
You may have some invisible special character not removed by trim — bfavaretto
– bfavaretto, Commented Oct 4, 2012 at 0:17
I don't understand what's asked here. For any non-empty string in key, key != '' will evaluate to true, and !key will evaluate to false. — raina77ow
– raina77ow, Commented Oct 4, 2012 at 0:17
@user1689607 Good call. key.length is 1, key.charCodeAt(0) is 8203. I think I can solve this by checking if key.length > 1 — Jonathan Eckman
– Jonathan Eckman, Commented Oct 4, 2012 at 0:32

bfavaretto · Accepted Answer · 2012-10-04 00:51:30Z

1

I said in the comments it might be an invisible character not stripped by trim. Well, after your further comments, it's clear that's the case. It's the U+200B Zero-width space character. It probably came from jsfiddle (I'm betting you pasted something from there).

answered Oct 4, 2012 at 0:51

bfavaretto

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