The following are two methods of building a link that has the sole purpose of running JavaScript code. Which is better, in terms of functionality, page load speed, validation purposes, etc.?

function myJsFunc() {
    alert("myJsFunc");
}
<a href="#" onclick="myJsFunc();">Run JavaScript Code</a>

or

function myJsFunc() {
    alert("myJsFunc");
}
 <a href="javascript:void(0)" onclick="myJsFunc();">Run JavaScript Code</a>
javascript html performance optimization href 

Nov 17

5 Answers

I use javascript:void(0).

Three reasons. Encouraging the use of # amongst a team of developers inevitably leads to some using the return value of the function call like this:

function doSomething() {
    //Some code
    return false;
}

But then they forget to use return doSomething() in the onclick and just use doSomething().

A second reason for avoiding # is that the final return false; will not execute if the called function throws an error. Hence the developers have to also remember to handle any error appropriately in the called function.

A third reason is that there are cases where the onclick event property is assigned dynamically. I prefer to be able to call a function or assign it dynamically without having to code the function specifically for one method of attachment or another. Hence my onclick (or on anything) in HTML markup look like this:

onclick="someFunc.call(this)"

OR

onclick="someFunc.apply(this, arguments)"

Using javascript:void(0) avoids all of the above headaches, and I haven't found any examples of a downside.

So if you're an alone developer then you can clearly make your own choice, but if you work as a team you have to either state:

Use href="#", make sure onclick always contains return false; in the end, that any called function does not throw an error, and if you attach a function dynamically to the onclick property make sure that as well as not throwing an error it returns false.

OR

Use href="javascript:void(0)"

The second is clearly much easier to communicate.

answered Jan 10


'#' will take the user back to the top of the page, so I usually go with void(0).

javascript:; also behaves like javascript:void(0);

answered Jan 10


The first one, ideally with a real link to follow in case the user has JavaScript disabled. Just make sure to return false to prevent the click event from firing if the JavaScript executes.

<a href="#" onclick="myJsFunc(); return false;">Link</a>

If you use Angular2, this way works:

<a [routerLink]="" (click)="passTheSalt()">Click me</a>.

answered Jan 10


Ideally, you'd do this:

<a href="javascriptlessDestination.html" onclick="myJSFunc(); return false;">Link text</a>

Or, even better, you'd have the default action link in the HTML, and you'd add the onclick event to the element unobtrusively via JavaScript after the DOM renders, thus ensuring that if JavaScript is not present/utilized you don't have useless event handlers riddling your code and potentially obfuscating (or at least distracting from) your actual content.

answered Jan 10


The void operator evaluates the given expression and then returns undefined.

The void operator is often used merely to obtain the undefined primitive value, usually using “void(0)” (which is equivalent to “void 0”). In these cases, the global variable undefined can be used instead (assuming it has not been assigned to a non-default value).

An explanation is provided here: void operator.

The reason you’d want to do this with the href of a link is that normally, a javascript: URL will redirect the browser to a plain text version of the result of evaluating that JavaScript. But if the result is undefined, then the browser stays on the same page. void(0) is just a short and simple script that evaluates to undefined.

answered Jan 10


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