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So I see a lot of JavaScript code (have written some myself) that does something like
<script> function CallSomeFunction() { //function body } $(document).ready(function () { callSomeFunction(); return false; }); and at other times:
callSomeFunction(); return true; Basically I've never understood the true use of the return true/false after function calls in JavaScript. I've just assumed its some kind of magic I need my functions to run well.
So please I'd like to know why? why do we use return true or return false after calling a JavaScript function?
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returning true or false indicates that whether execution should continue or stop right there. So just an example <input type="button" onclick="return func();" /> Now if func() is defined like this function func() { // do something return false; }
No, return; is the same as return undefined; , which is the same as having a function with no return statement at all.
Return statements, in programming languages, are used to skip the currently executing function and return to the caller function. Return statements may/may not return any value. Below is the example of a return statement in JavaScript.
The return statement ends function execution and specifies a value to be returned to the function caller.
Return statements, in programming languages, are used to skip the currently executing function and return to the caller function. Return statements may/may not return any value. Below is the example of a return statement in JavaScript. Example 2: Similarly, we can return true or false in a simple JavaScript function.
Your code makes no sense, maybe because it's out of context. The return false will return false to the click-event. That tells the browser to stop following events, like follow a link. It has nothing to do with the previous function call. Javascript runs from top to bottom more or less, so a line cannot affect a previous line.
Developers use the return false in many different cases.For example, Depending upon boolean (true or false) value If a form field (fname) is empty, then function alerts a message, and returns false, to prevent the form from being submitted.
Javascript runs from top to bottom more or less, so a line cannot affect a previous line. returning true or false indicates that whether execution should continue or stop right there. the click event will never get executed. On the contrary if return true is written then the click event will always be executed.
I think a lot of times when you see this code, it's from people who are in the habit of event handlers for forms, buttons, inputs, and things of that sort.
Basically, when you have something like:
<form onsubmit="return callSomeFunction();"></form> or
<a href="#" onclick="return callSomeFunction();"></a>` and callSomeFunction() returns true, then the form or a will submit, otherwise it won't.
Other more obvious general purposes for returning true or false as a result of a function are because they are expected to return a boolean.
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