Events

Until now all the tutorials were about the simple statements which were run or executed at the moment when the web page is loaded. But if we have to run the program only when a button is clicked, what we can do. For this we can use events.
Events are actions or occurrences that happen in the system you are programming, which the system tells you about so you can respond to them in some way if desired.
An event is nothing more than a signal. It communicates that something has just happened. This something could be a mouse click, key press on the keyboard, window getting resized  and so on.

Onclick is most frequently used event type. So let’s do an example with onclick event.

The result we got is,

When we click the button, the following alert is shown.

You can change the event instead 'onclick' and see the result.

JavaScript events are listed in below table. Thank you for watching this tutorial and if you have any questions don't forget to mention them in comments.

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