prototypejs – Testing the type of a DOM element in JavaScript-ThrowExceptions

Exception or error:

Is there a way to test the type of an element in JavaScript?

The answer may or may not require the prototype library, however the following setup does make use of the library.

function(event) {
  var element = event.element();
  // if the element is an anchor
  ...
  // if the element is a td
  ...
}
How to solve:

You can use typeof(N) to get the actual object type, but what you want to do is check the tag, not the type of the DOM element.

In that case, use the elem.tagName or elem.nodeName property.

if you want to get really creative, you can use a dictionary of tagnames and anonymous closures instead if a switch or if/else.

###

if (element.nodeName == "A")
{
}
else if (element.nodeName == "TD")
{
}

###

Perhaps you’ll have to check the nodetype too:

if(element.nodeType == 1){//element of type html-object/tag
  if(element.tagName=="a"){
    //this is an a-element
  }
  if(element.tagName=="div"){
    //this is a div-element
  }
}

Edit: Corrected the nodeType-value

###

roenving is correct BUT you need to change the test to:

if(element.nodeType == 1) {
//code
}

because nodeType of 3 is actually a text node and nodeType of 1 is an HTML element. See http://www.w3schools.com/Dom/dom_nodetype.asp

###

I usually get it from the toString() return value. It works in differently accessed DOM elements:

var a = document.querySelector('a');

var img = document.createElement('img');

document.body.innerHTML += '<div id="newthing"></div>';
var div = document.getElementById('newthing');

Object.prototype.toString.call(a);    // "[object HTMLAnchorElement]"
Object.prototype.toString.call(img);  // "[object HTMLImageElement]"
Object.prototype.toString.call(div);  // "[object HTMLDivElement]"

Then the relevant piece:

Object.prototype.toString.call(...).split(' ')[1].slice(0, -1);

It works in Chrome, FF, Opera, Edge, IE9+ (in older IE it return “[object Object]”).

###

Although the previous answers work perfectly, I will just add another way where the elements can also be classified using the interface they have implemented.

Refer W3 Org for available interfaces

console.log(document.querySelector("#anchorelem") instanceof HTMLAnchorElement);
console.log(document.querySelector("#divelem") instanceof HTMLDivElement);
console.log(document.querySelector("#buttonelem") instanceof HTMLButtonElement);
console.log(document.querySelector("#inputelem") instanceof HTMLInputElement);
<a id="anchorelem" href="">Anchor element</a>
<div id="divelem">Div Element</div>
<button id="buttonelem">Button Element</button>
<br><input id="inputelem">

The interface check can be made in 2 ways as elem instanceof HTMLAnchorElement or elem.constructor.name == "HTMLAnchorElement", both returns true

###

I have another way of testing the same.

Element.prototype.typeof = "element";
var element = document.body; // any dom element
if (element && element.typeof == "element"){
   return true; 
   // this is a dom element
}
else{
  return false; 
  // this isn't a dom element
}

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