UncaCannot set property 'innerHTML' of null

Question

Please help me whats wrong code ?

function runPrompt(Message, promptLocation, color)
{
document.getElementById("promptLocation").innerHTML = Message;
document.getElementById("promptLocation").style.color = color;
}

Name : 
<input id= "commandName" onkeyup = "validateName()" type = "text"> <label id = "namePrompt"></label>

Just post a small part that has the element promptLocation in it — Wayne Ellery, Jan 03 '15 at 08:58
possible duplicate of [Why does jQuery or a DOM method such as getElementById not find the element?](http://stackoverflow.com/questions/14028959/why-does-jquery-or-a-dom-method-such-as-getelementbyid-not-find-the-element) — Teemu, Jan 03 '15 at 09:00
done this name, i want to validate this name, i want to prompt tell on the right the textbox — Antoni Angga, Jan 03 '15 at 09:01
If parameter `promptLocation` in your function should contain the element id then simply remove the quotes in the `getElementById` call. — Dirk Lachowski, Jan 03 '15 at 09:03
you are using promptLocation in your document.getElementById("promptLocation").innerHTML as id then try doing this:document.getElementById("'"+promptLocation+"'").innerHTML — Suchit kumar, Jan 03 '15 at 09:04

score 1 · Accepted Answer · answered Jan 03 '15 at 09:04

It's unclear what you are after without posting your html. I think you are trying to use promptLocation parameter as the id of the element to change. The parameter variable should be passed directly into getElementById and shouldn't be in quotes:

<div id="namePrompt"></div>

function runPrompt(Message, promptLocation, color)
{
    document.getElementById(promptLocation).innerHTML = Message;
    document.getElementById(promptLocation).style.color = color;
}

runPrompt('Test Message', 'namePrompt', 'red');

http://jsfiddle.net/jq8ghxkb/1/

score 0 · Answer 2 · answered Jan 03 '15 at 09:11

For safer side we need to check whether element is exist or not while using 'document.getElementById'. Because we can't access the attributes of undefined/no rendered elements in JavaScript.

In case of JQuery, $('#id') will give empty array if id is not exist.

UncaCannot set property 'innerHTML' of null

2 Answers2