javascript - chrome violation : [Violation] Handler took 83ms of runtime

问题

I'm trying to implement the Facebook's logout functionality in my project. Login works just fine. But i'm facing the getting the following message in JavaScript console with the logout code.

[Violation] Long running JavaScript task took 318ms session.php:51 1 sdk.js:135

[Violation] Handler took 83ms of runtime (50ms allowed)

I've tried to search for other similar threads and those solutions didn't work out for me. I tried removing parts of my code and see which part is giving problem. Its quite clear that its getting the error due to Facebook's JS SDK as seen in the message. I've also disabled all of my Chrome extensions.

The code works fine in Firefox but not in Chrome, nor in Opera. Is there any method for me to extend this timeout duration? Or any other method to fix this issue in chrome. Here is my code for logout.

<?php
    session_start();
    //echo $_SESSION["current_user"];
    //echo $_COOKIE["current_user"];
    session_destroy();
    unset($_COOKIE["current_user"]);
    setcookie("current_user","",time() -3600, "/","", 0);
    //header("location: login.php");
?>

<!doctype html>

<html>
<head>
</head>
<body>

<script>

    // Default settings
    window.fbAsyncInit = function() {
        FB.init({
            appId      : '<app-id>',
            cookie     : true,
            xfbml      : true,
            version    : 'v2.8'
        });
        FB.AppEvents.logPageView();   
    };

    (function(d, s, id){
        var js, fjs = d.getElementsByTagName(s)[0];
        if (d.getElementById(id)) {return;}
        js = d.createElement(s); js.id = id;
        js.src = "//connect.facebook.net/en_US/sdk.js";
        fjs.parentNode.insertBefore(js, fjs);
    }(document, 'script', 'facebook-jssdk'));

    window.onload = function(){
        logout();
    }
    function logout(){
        console.log("1");
        FB.getLoginStatus(function(response) {
        if (response.status === 'connected') {
            FB.logout();
            console.log("2");
            window.location="login.php";
            console.log("3");
        }
        else{
            console.log("4");
            window.location="login.php";
            console.log("5");
        }
        });
    }
</script>
</body>
</html>

For obvious reasons I've removed the App-Id from the code. Any help is appreciated. :)

回答1:

"Chrome violations" don't represent errors in either Chrome or your own web app. They are instead warnings to help you improve your app. In this case, Long running JavaScript and took 83ms of runtime are alerting you there's probably an opportunity to speed up your script.

("Violation" is not the best terminology; it's used here to imply the script "violates" a pre-defined guideline, but "warning" or similar would be clearer. These messages first appeared in Chrome in early 2017 and should ideally have a "More info" prompt to elaborate on the meaning and give suggested actions to the developer. Hopefully those will be added in the future.)

回答2:

Perhaps a little off topic, just be informed that these kind of messages can also be seen when you are debugging your code with a breakpoint inside an async function like setTimeout like below:

[Violation] 'setTimeout' handler took 43129ms

That number (43129ms) depends on how long you stop in your async function

回答3:

It seems you have found your solution, but still it will be helpful to others, on this page on point

4.Note the red triangle in the top-right of the Animation Frame Fired event. Whenever you see a red triangle, it's a warning that there may be an issue related to this event.

If you hover on these triangle you can see those are the violation handler errors and as per point 4. yes there is some issue related to that event.

来源：https://stackoverflow.com/questions/42218699/javascript-chrome-violation-violation-handler-took-83ms-of-runtime

标签

javascript

google-chrome

facebook-javascript-sdk