How to check if some field does not exist in JavaScript - Stack Overflow

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I have jQuery code like

      for(var j in indivudvalbookdetails) {
         if(indivudvalbookdetails[j]['status'] == "") {
          ... 
         }
     }

Now there might be some items in the loop where status field won't exists, if there are such items the code in the if condition should work.

I have jQuery code like

      for(var j in indivudvalbookdetails) {
         if(indivudvalbookdetails[j]['status'] == "") {
          ... 
         }
     }

Now there might be some items in the loop where status field won't exists, if there are such items the code in the if condition should work.

• javascript

Share Improve this question Follow edited Dec 17, 2021 at 23:52 halfer 20.4k1919 gold badges109109 silver badges202202 bronze badges asked Nov 5, 2017 at 9:59 NidaNida 1,70233 gold badges3636 silver badges7575 bronze badges 3

• Instead of the empty character, check for undefined, and use strict parison operator. – Teemu Commented Nov 5, 2017 at 10:04
• can u show me in the code – Nida Commented Nov 5, 2017 at 10:08
• This is pure javascript, theres no jquery involved here. – Jonas Wilms Commented Nov 5, 2017 at 10:29

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4 Answers 4

Sorted by: Reset to default 2

Try this:

var myElement =  indivudvalbookdetails[j]['status'];
if (typeof(myElement) != 'undefined' && myElement != null)
{
  // exists.
}

You can also try with JQuery like:

if ($('#elementId').length > 0) {
  // exists.
}

Just check if its undefined:

if(typeof indivudvalbookdetails[j]['status'] === "undefined") { ...

Your code is paring your variable to an empty string. But if this variable is not defined, it can’t pare it, so you can do :

if(indivudvalbookdetails[j]['status'] == undefined)

If the « status » var is defined but just empty you can do

 if(indivudvalbookdetails[j]['status'] == null)

You check like this

if(!indivudvalbookdetails[j]['status'])

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