javascript函数调用的语法差异？

Question

What is the difference between:

<div onclick="return function()"></div>

vs

<div onclick="function()"></div> 

They seem to be doing the same thing for me and I am not sure which one to use.

Answer 1

Take for example <form onsubmit="return validate();">... The submit will be cancelled if validate() returns false.

With <form onsubmit="validate();">... The submit will continue regardless of the return value of validate().

Answer 2

Explanation in words..

One will return the value to the element which the attribute resides in, the other will not.

When you use return function () the default click-method of the element will only be executed if function () evaluates to a value that implicitly is converted to true .

If it yields false the evaluation of the click-event will halt after running the onclick -property.

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In case of onclick="function ()" the default click-propery of the element will always be executed, no matter what the function returns.

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Example snippets with detailed information of what is happening..

function some_func () { return false; }

<a href="http://google.com" onclick="return some_func()">
  link #1
</a> <!-- user will never end up at google -->

^{if javascript is enabled in the browser, of course..}

<a href="http://google.com" onclick="some_func()">
  link #1
</a> <!-- user will always end up at google -->

Answer 3

There is a difference, if you write return, it will check if the return is true or false and will only take action if return is true. otherwise it will just process.