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HTML Reference

Quick Reference

The onbeforeunload event fires when the user has made an action to leave the current page. Most browsers provide a default message and will ignore the message you provide in the JavaScript return.

Supported HTML tags:

				
					<!-- HTML -->
<body onbeforeunload="return my_function()">
				
			
				
					// JavaScript
function my_function() {
    return 'This message is unlikely to be used by the browser.';
}

JavaScript

Both of the following are valid.

onbeforeunload

				
					window.onbeforeunload = function(event) {
  	event.returnValue = 'This message is unlikely to be used by the browser.';
};

beforeunload

				
					window.addEventListener('beforeunload', function(event) {
  	event.returnValue = 'This message is unlikely to be used by the browser.';
});

Event

Bubbles no
Can be canceled yes

We’d like to acknowledge that we learned a great deal of our coding from W3Schools and TutorialsPoint, borrowing heavily from their teaching process and excellent code examples. We highly recommend both sites to deepen your experience, and further your coding journey. We’re just hitting the basics here at 1SMARTchicken.

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jQuery
PHP
SQL
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HTML NOTES:

  • In our HTML section the term “tag” and “element” are often used interchangeably to refer to both the tag used to create a page element and the element created by the tag (p tag = p element = paragraph on the page)
  • HTML5 is not case sensitive; so P is the same as p, H1 is the same as h1
  • Global attributes can be used with all HTML tags and are therefore not mentioned on every tag page
  • To write clean, readable HTML code, it is best to use indentation whereas elements within elements are indented (tabbed or spaces) to create something that looks like a project outline
  • The browser will automatically remove any extra spaces and lines in your HTML code when the page is displayed
  • Double quotes or single quotes can be used around HTML attribute values, but when the attribute value itself contains one form of quote, it will be necessary to use the other around the attribute

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If you see an error on the page or the code itself is incorrect or incomplete, or just plain wrong, please let us know. We’re always learning. NOTE: we do not sell your information and will not send you spam emails.

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