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JavaScript - DOM Events

The DOM events are actions that can be performed on HTML elements. When an event occurs, it triggers a JavaScript function. This function can then be used to change the HTML element or perform other actions.

Here are some examples of DOM events:

  • Click − This event occurs when a user clicks on an HTML element.

  • Load − This event occurs when an HTML element is loaded.

  • Change − This event occurs when the value of an HTML element is changed.

  • Submit − This event occurs when an HTML form is submitted.

You can use the event handlers or addEventListener() method to listen to and react to the DOM events. The addEventListener() method takes two arguments: the name of the event and the function that you want to be called when the event occurs.

The DOM events are also referred as Document Object Model events. It is used to interact with the DOM elements and manipulate the DOM elements from JavaScript when any event occurs.

Let's look at the below examples of DOM events.

The onclick Event Type

This is the most frequently used event type which occurs when a user clicks the left button of his mouse. You can put your validation, warning etc., against this event type.

Example

Try the following example.

<html>
<head>   
   <script>
	  function sayHello() {
		 alert("Hello World")
	  }
   </script>      
</head>   
<body>
   <p>Click the following button and see result</p>      
   <form>
	  <input type = "button" onclick = "sayHello()" value = "Say Hello" />
   </form>      
</body>
</html>

The ondblclick Event Type

We use the 'ondblclick' event handler in the code below with the element. When users double click the button, it calls the changeColor() function.

In the changeColor() function, we change the color of the text. So, the code will change the text's color when the user double-clicks the button.

Example

<html>
<body>
   <h2 id = "text"> Hi Users! </h2>
   <button ondblclick="changeColor()"> Double click me! </button>
   <script>
      function changeColor() {
         document.getElementById("text").style.color = "red";
     }
   </script>
</body>
</html>

The onkeydown Event Type

We used the 'keydown' event in the code below with the <input> element. Whenever the user will press any key, it will call the customizeInput() function.

In the customizeInput() function, we change the background color of the input and the input text to red.

Example

<html>
<body>
   <p> Enter charater/s by pressing any key  </p>
   <input type = "text" onkeydown = "customizeInput()">
   <script>
      function customizeInput() {
         var ele = document.getElementsByTagName("INPUT")[0];
         ele.style.backgroundColor = "yellow";
         ele.style.color = "red";
      }
   </script>
</body>

The onmouseenter and onmouseleave Events

In the code below, we use the 'onmouseenter' and 'onmouseleave' event handlers to add a hover effect on the <div> element.

When the mouse pointer enters the <div> element, it calls the changeRed() function to change the text color to red, and when the mouse pointer leaves the <div> element, it calls the changeBlack() function to change the text color to black again.

Example

<html>
<body>
   <div id = "text" style = "font-size: 20px;" onmouseenter = "changeRed()" onmouseleave = "changeBlack()"> Hover over the text. </div>
   <script>
      function changeRed() {
         document.getElementById("text").style.color = "red";
      }
      function changeBlack() {
         document.getElementById("text").style.color = "black";
      }
   </script>
</body>
</html>

HTML 5 Standard DOM Events

The standard HTML 5 events are listed here for your reference. Here script indicates a Javascript function to be executed against that event.

Attribute Value Description
Offline script Triggers when the document goes offline
Onabort script Triggers on an abort event
onafterprint script Triggers after the document is printed
onbeforeonload script Triggers before the document loads
onbeforeprint script Triggers before the document is printed
onblur script Triggers when the window loses focus
oncanplay script Triggers when media can start play, but might has to stop for buffering
oncanplaythrough script Triggers when media can be played to the end, without stopping for buffering
onchange script Triggers when an element changes
onclick script Triggers on a mouse click
oncontextmenu script Triggers when a context menu is triggered
ondblclick script Triggers on a mouse double-click
ondrag script Triggers when an element is dragged
ondragend script Triggers at the end of a drag operation
ondragenter script Triggers when an element has been dragged to a valid drop target
ondragleave script Triggers when an element is being dragged over a valid drop target
ondragover script Triggers at the start of a drag operation
ondragstart script Triggers at the start of a drag operation
ondrop script Triggers when dragged element is being dropped
ondurationchange script Triggers when the length of the media is changed
onemptied script Triggers when a media resource element suddenly becomes empty.
onended script Triggers when media has reach the end
onerror script Triggers when an error occur
onfocus script Triggers when the window gets focus
onformchange script Triggers when a form changes
onforminput script Triggers when a form gets user input
onhaschange script Triggers when the document has change
oninput script Triggers when an element gets user input
oninvalid script Triggers when an element is invalid
onkeydown script Triggers when a key is pressed
onkeypress script Triggers when a key is pressed and released
onkeyup script Triggers when a key is released
onload script Triggers when the document loads
onloadeddata script Triggers when media data is loaded
onloadedmetadata script Triggers when the duration and other media data of a media element is loaded
onloadstart script Triggers when the browser starts to load the media data
onmessage script Triggers when the message is triggered
onmousedown script Triggers when a mouse button is pressed
onmousemove script Triggers when the mouse pointer moves
onmouseout script Triggers when the mouse pointer moves out of an element
onmouseover script Triggers when the mouse pointer moves over an element
onmouseup script Triggers when a mouse button is released
onmousewheel script Triggers when the mouse wheel is being rotated
onoffline script Triggers when the document goes offline
onoine script Triggers when the document comes online
ononline script Triggers when the document comes online
onpagehide script Triggers when the window is hidden
onpageshow script Triggers when the window becomes visible
onpause script Triggers when media data is paused
onplay script Triggers when media data is going to start playing
onplaying script Triggers when media data has start playing
onpopstate script Triggers when the window's history changes
onprogress script Triggers when the browser is fetching the media data
onratechange script Triggers when the media data's playing rate has changed
onreadystatechange script Triggers when the ready-state changes
onredo script Triggers when the document performs a redo
onresize script Triggers when the window is resized
onscroll script Triggers when an element's scrollbar is being scrolled
onseeked script Triggers when a media element's seeking attribute is no longer true, and the seeking has ended
onseeking script Triggers when a media element's seeking attribute is true, and the seeking has begun
onselect script Triggers when an element is selected
onstalled script Triggers when there is an error in fetching media data
onstorage script Triggers when a document loads
onsubmit script Triggers when a form is submitted
onsuspend script Triggers when the browser has been fetching media data, but stopped before the entire media file was fetched
ontimeupdate script Triggers when media changes its playing position
onundo script Triggers when a document performs an undo
onunload script Triggers when the user leaves the document
onvolumechange script Triggers when media changes the volume, also when volume is set to "mute"
onwaiting script Triggers when media has stopped playing, but is expected to resume
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