jQuery: Wait/Delay 1 second without executing code

2019-01-21 02:10发布

站内文章 / JavaScript
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问题:

I can't get the .delay method working in jQuery:

$.delay(3000); // not working
$(queue).delay(3000); // not working

I'm using a while loop to wait until an uncontrolled changing value is greater than or equal to another and I can't find any way to hault execution for X seconds.

回答1:

$.delay is used to delay animations in a queue, not halt execution.

Instead of using a while loop, you need to recursively call a method that performs the check every second using setTimeout:

var check = function(){
    if(condition){
        // run when condition is met
    }
    else {
        setTimeout(check, 1000); // check again in a second
    }
}

check();


回答2:

You can also just delay some operation this way:

setTimeout(function (){

  // Something you want delayed.

}, 5000); // How long do you want the delay to be (in milliseconds)?


回答3:

jQuery's delay function is meant to be used with effects and effect queues, see the delay docs and the example therein:

$('#foo').slideUp(300).delay(800).fadeIn(400);

If you want to observe a variable for changes, you could do something like

(function() {
    var observerInterval = setInterval(function() {
        if (/* check for changes here */) {
           clearInterval(observerInterval);
           // do something here
        }
    }, 1000);
})();


回答4:

JavaScript setTimeout is a very good solution:

function funcx()
   {
   // your code here
   // break out here if needed
   setTimeout(funcx, 3000);
   }

funcx();

The delay function in jQuery is mostly used for delaying animations in a jQuery animation queue.



回答5:

delay() doesn't halt the flow of code then re-run it. There's no practical way to do that in JavaScript. Everything has to be done with functions which take callbacks such as setTimeout which others have mentioned.

The purpose of jQuery's delay() is to make an animation queue wait before executing. So for example $(element).delay(3000).fadeIn(250); will make the element fade in after 3 seconds.



回答6:

Only javascript It will work without jQuery 

<!DOCTYPE html>
<html>
    <head>
        <script>
            function sleep(miliseconds) {
                var currentTime = new Date().getTime();
                while (currentTime + miliseconds >= new Date().getTime()) {
                }
            }

            function hello() {
                sleep(5000);
                alert('Hello');
            }
            function hi() {
                sleep(10000);
                alert('Hi');
            }
        </script>
    </head>
    <body>
        <a href="#" onclick="hello();">Say me hello after 5 seconds </a>
        <br>
        <a href="#" onclick="hi();">Say me hi after 10 seconds </a>


    </body>
</html>


回答7:

Javascript is an asynchronous programming language so you can't stop the execution for a of time; the only way you can [pseudo]stop an execution is using setTimeout() that is not a delay but a "delayed function callback".



回答8:

es6 setTimeout

setTimeout(() => {
  console.log("we waited 204586560000 ms to run this code, oh boy wowwoowee!");
}, 204586560000);

Edit: 204586560000 ms is the approximate time between the original question and this answer... assuming I calculated correctly.



标签： javascript jquery delay wait seconds
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