84 lines
2.5 KiB
Markdown
84 lines
2.5 KiB
Markdown
---
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title: What Does JavaScript Void 0 Mean
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---
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## What Does JavaScript Void 0 Mean
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**JavaScript's void operator evaluates an expression and returns undefined**.
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Using console to verify the same :-
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***Note*** :- **void** irrespective of any value passed along , *always returns **undefined** as shown above*.
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But, **void with operand 0 is preferred**.
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**Two ways of using operand 0 -> void(0) or void 0.** Either of them is fine.
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#### When to use Javascript void (0) ?
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When on link click, you don't want the browser to load a new page or refresh the same page( depending on the URL specified ).
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Instead,perform the JavaScript attached to that link.
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#### Sample Example 1 with Javascript void (0) :
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```html
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<html>
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<body>
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<a href="javascript:void(0);alert('Hello ! I am here')">Click Me</a>
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</body>
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</html>
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```
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#### Output :
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When clicked on ClickMe link,an alert pops up as below :
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#### Sample Example 2 with Javascript void (0) :
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```html
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<html>
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<body>
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<a href="javascript:void(0)" ondblclick="alert('Hi,i didnt refresh the page')" )>Click Me</a>
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</body>
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</html>
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```
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#### Output :
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When you double click the link,an alert will popup without any page refresh.
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#### Sample Example 3 with Javascript void (0) :
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```html
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<html>
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<body>
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<a href="javascript:void(0);https://www.google.co.in/"
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ondblclick="alert('Hello !! You will see me and not get redirected to google.com ')">Click Me</a>
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</body>
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</html>
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```
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#### Output :
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When you double click the link,an alert will popup,closing it will also not redirect to google.com.
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#### Sample Example without Javascript void (0) :
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```html
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<html>
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<body>
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<a href="https://www.google.co.in/" ondblclick="alert('Hello !! You will see me and then get redirected to google.com even if not needed')">Click Me</a>
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</body>
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</html>
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```
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#### Output :
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When you double click the link,an alert will popup, closing it will redirect to google.com.
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#### Conclusion :
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**void** operator is useful when you need to prevent any unwanted page refresh or redirection.
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Rather,perform some javascript operation.
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#### More Information:
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1) <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/void' target='_blank' rel='nofollow'>Mozilla Docs</a>
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2) <a href='https://www.quackit.com/javascript/tutorial/javascript_void_0.cfm' target='_blank' rel='nofollow'>Understanding void 0</a>
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