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Summary of similarities and differences between onbeforeunload and onunload events_javascript skills
- WBOYOriginal
- 2016-05-16 17:31:281000browse
1) Similarities and differences
Same points: onunload and onbeforeunload are called when refreshing or closing. They can be specified through window.onunload in the <script> script or specified in <body>. <BR>Differences: <BR>a) onbeforeunload is executed before onunload, and it can also prevent the execution of onunload. <BR>b) onbeforeunload is called when going to the server to read a new page, but has not yet started reading; nunload has read the new page that needs to be loaded from the server, and is called when the current page is about to be replaced. <BR>c) onbeforeunload can prevent the page from being updated and closed. But onunload cannot. <BR>The execution sequence of onload, onbeforeunload, and onunload events: <BR>When opening the page: only execute onload <BR>When closing the page: first onbeforeunload, then onunload <BR>When refreshing the page: first onbeforeunload, then onunload, then onload <br><br><STRONG>2) onbeforeunload, onunload events <BR>Triggered when: <BR>a) Close the browser window<BR>b) When going to other pages through the address bar or favorites<BR>c) When clicking return, forward, refresh, or one of the homepages <BR>d) When clicking a URL link to other pages <BR>e) When calling any of the following events: click, document write, document open, document close, window close, window navigate, window NavigateAndFind, location replace, location reload, form submit. <BR>f) When using window open to open a page, pass the name of the window on this page to the page to be opened. time. <BR>g) When reassigning the value of location.href. <BR>h) When submitting a form with a specified action through the input type="submit" button. <BR> can be used in the following elements: <BR>BODY, FRAMESET, window <BR>Browser support: <BR>IE4 /Win, Mozilla 1.7a, Netscape 7.2, Firefox0.9 <br><br><STRONG> 3) Solve the problem of not calling onbeforeunload when refreshing the page <br><br><STRONG>4) onbeforeunload prevents the update and closing of the page <BR>onbeforeunload="return 'Do you want to leave this page now';"></script>
Same points: onunload and onbeforeunload are called when refreshing or closing. They can be specified through window.onunload in the <script> script or specified in <body>. <BR>Differences: <BR>a) onbeforeunload is executed before onunload, and it can also prevent the execution of onunload. <BR>b) onbeforeunload is called when going to the server to read a new page, but has not yet started reading; nunload has read the new page that needs to be loaded from the server, and is called when the current page is about to be replaced. <BR>c) onbeforeunload can prevent the page from being updated and closed. But onunload cannot. <BR>The execution sequence of onload, onbeforeunload, and onunload events: <BR>When opening the page: only execute onload <BR>When closing the page: first onbeforeunload, then onunload <BR>When refreshing the page: first onbeforeunload, then onunload, then onload <br><br><STRONG>2) onbeforeunload, onunload events <BR>Triggered when: <BR>a) Close the browser window<BR>b) When going to other pages through the address bar or favorites<BR>c) When clicking return, forward, refresh, or one of the homepages <BR>d) When clicking a URL link to other pages <BR>e) When calling any of the following events: click, document write, document open, document close, window close, window navigate, window NavigateAndFind, location replace, location reload, form submit. <BR>f) When using window open to open a page, pass the name of the window on this page to the page to be opened. time. <BR>g) When reassigning the value of location.href. <BR>h) When submitting a form with a specified action through the input type="submit" button. <BR> can be used in the following elements: <BR>BODY, FRAMESET, window <BR>Browser support: <BR>IE4 /Win, Mozilla 1.7a, Netscape 7.2, Firefox0.9 <br><br><STRONG> 3) Solve the problem of not calling onbeforeunload when refreshing the page <br><br><STRONG>4) onbeforeunload prevents the update and closing of the page <BR>onbeforeunload="return 'Do you want to leave this page now';"></script>
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