TypeError: document.getElementById(...) is null in javascript

Question

This is my coding for dynamic field validation. if i use this function i got 'TypeError: document.getElementById(...) is null' this kind of error.

function sr_answer_val(){
  var cnt=parseInt(document.getElementById("add_field_cnt").value);
  var submitAllow=true;
  for(var i=1;i<cnt;i++){
    if(document.getElementById("cust_field_"+i).value ==''){
      alert('Answer Should be Mandatory');
      submitAllow=false;
      return false;     
    }
  }
}

Check the HTML, if there are really all elements present (at the time of execution) you want to access. — Sirko, Jan 20 '14 at 10:53
http://stackoverflow.com/questions/14028959/why-does-jquery-or-a-dom-method-such-as-getelementbyid-not-find-the-element — basilikum, Jan 20 '14 at 10:54
Please provide your HTML markup too. Check if the element __add_field_cnt__ and __cust_field___ exist in yur page — Irvin Dominin, Jan 20 '14 at 10:57

score 0 · Answer 1 · answered Jan 20 '14 at 10:55

0

There's for sure no element with id named "add_field_cnt" in your html. Check if there's no any typo.

answered Jan 20 '14 at 10:55

lukaleli

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score 0 · Answer 2 · edited May 23 '17 at 12:21

0

Your element add_field_cnt is (DOM) not loaded/created.

I guess you're loading the js in head, instead do it at the bottom of body or use document.ready

edited May 23 '17 at 12:21

Community

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1

answered Jan 20 '14 at 10:56

Praveen

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score 0 · Answer 3 · answered Jan 20 '14 at 11:00

The element with id passed to getElementById() does not exist. So, you can do a null check

var elem = document.getElementById("add_field_cnt");
if(typeof elem !== 'undefined' && elem !== null) {
    var cnt = parseInt(document.getElementById(elem).value);
    .......// do your stuff
}

score 0 · Answer 4 · answered Jan 20 '14 at 11:00

0

There is no element with the ID add_field_cnt so you are getting this error

var cnt=parseInt(document.getElementById("add_field_cnt").value);

please check your element is Created or not with add_field_cnt ID.

i hope so.

answered Jan 20 '14 at 11:00

Govinda Rajbhar

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score 0 · Accepted Answer · answered Jan 20 '14 at 11:11

Probably your custom fields are not all defined, so when you try to acces one of them it is undefined.

Check the existence of the element before accesing it like:

function sr_answer_val() {
    var cnt = parseInt(document.getElementById("add_field_cnt").value);
    var submitAllow = true;
    for (var i = 1; i < cnt; i++) {
        if (document.getElementById("cust_field_" + i) && document.getElementById("cust_field_" + i).value == '') {
            alert('Answer Should be Mandatory');
            submitAllow = false;
            return false;
        }
    }
}

Demo: http://jsfiddle.net/IrvinDominin/X3ZnQ/

TypeError: document.getElementById(...) is null in javascript

5 Answers5