Setting innerHTML: Why won't it update the DOM?

Question

Wondering why I can\'t get document.getElementById(\"my_div\").innerHTML to update the DOM when I re-assign the variable. For example:

        
                      

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Answer 1

you need to reassign the element after setting innerHTML/outerHTML:

let indexInParent=[].slice.call(elem.parentElement.children).indexOf(elem);
elem.innerHTML=innerHTML;
elem=elem.parentElement.children[indexInParent];

Answer 2

For future googlers my problem was that I was calling the plural elements.

document.getElementsByClassName(‘class’).innerHTML

So it returned an Array not a single element. I changed it to the singular.

document.getElementByClassName(‘class’).innerHTML

That made it so I could update the innerHTML value.

Answer 3

innerHTML evaluates to a string. I'm not sure why you would expect anything different. Consider this:

var a = 'foo'; // now a = 'foo'
var b = a; // now a = 'foo', b = 'foo'
b = 'bar'; // now a = 'foo', b = 'bar'

Re-assigning b doesn't change a.

Edited to add: In case it's not clear from the above, if you want to change innerHTML, you can just assign to it directly:

document.getElementById("my_div").innerHTML = "Hello";

You don't need, and can't use, an intermediary variable.

Answer 4

you should set the innerHTML value like

 var myDivValue = document.getElementById("my_div").innerHTML = "Hello";

Answer 5

 var myDivValue = document.getElementById("my_div").innerHTML;

stores the value of innerHTML, innerHTML contains a string value, not an object. So no reference to the elem is possible. You must to store directly the object to modify its properties.

var myDiVElem = document.getElementById("my_div");
myDiVElem.innerHTML = 'Hello'; // this makes the change