how to stop timer with another function javascript

问题:

So I have this code

function timer()
{
     setTimeout(function(){alert("Out of time")}, 3000); //Alerts "Out of time" after 3000 milliseconds
}
function resetTime()
{
     timer(); //this is not right, i thought it would override the first function but it just adds another timer as well which is not what I want
}
function stopTime()
{
     //What could go here to stop the first function from fully executing before it hits 3000 milliseconds and displays the alert message?
}

the function timer() starts as the page loads but if I have a button for stopTime() and I click on it, how do I stop the first function from executing and stop it from hitting the 3000 millisecond mark and alerting "Out of time"?

回答1:

Use a variable with scope over all of your functions.

var myTimer;
...
myTimer = setTimeout(...);
...
clearTimeout(myTimer);

回答2:

var timer;

function timer()
{
    timer = setTimeout(function(){alert("Out of time")}, 3000); //Alerts "Out of time" after 3000 milliseconds
}
function resetTime()
{
    clearTimeout(timer);
     timer(); //this is not right, i thought it would override the first function but it just adds another timer as well which is not what I want
}
function stopTime()
{
     //What could go here to stop the first function from fully executing before it hits 3000 milliseconds and displays the alert message?
}

try this it will Work For you

回答3:

The value returned from setTimeout is a unique ID that you can use later to cancel the timeout with clearTimeout.

var timeout;

function timer () {
    timeout = setTimeout(/* ... */);
}

function resetTime() {
    stopTime();
    timer();
}

function stopTime() {
    clearTimeout(timeout);
}