I'm pretty new to (javascript) programming and I'm trying to get something automated.
There is a page that contains a countdown timer, and I want my greasemonkey script to automatically do some actions if the condition is met.
I've got this right now:
var timer = document.getElementById('timer_4975');
if (timer.innerHTML < "00:00:20"){
//Some actions
}
But this only checks the condition once when the script is loaded, when the timer goes under 00:00:20, it doesn't detect the condition is met and doesn't go to action.
Can someone guide me in the right direction?
Thanx in advance!
You can use the setTimeout or setInterval functions to perform this task.
setInterval will perform a task regularly, which is probably more suited to what you want to achieve.
Something like:
var timer = document.getElementById('timer_4975');
var intervalHandle = setInterval(function() {
if (timer.innerHTML < "00:00:20"){
//Some actions
clearInterval(intervalHandle);
}
},1000);
would check every second (1000ms). Change the 1000 value to increase or decrease the frequency of checking... once a second is likely to be often enough.
You will have to use setInterval() to execute your code more than once:
setInterval(function() {
if(timer.innerHTML < "00:00:20") {
//Some actions
}
}, 5000); //Execute this function each 5 seconds.
Related
Since setTimeout crashes in while loops.
I don't know if there is a way to do it but I am trying to make one.
This is how it looks so far.
<script>
var send = true;
function sendit()
{
alert("test");
return true;
}
while(true)
{
if(send == true)
{
send = false;
setTimeout(function(){
if(sendit() == true) {
send = true;
}
}, 5000);
}
}
</script>
Is it possible this way?
You haven't explained what you want your code to do. If you want it to alert "test" every 5 seconds then you need this:
<script>
function sendit()
{
alert("test");
// Call sendit() the next time, repeating
setTimeout(sendit, 5000);
}
// Call sendit() the first time
setTimeout(sendit, 5000);
</script>
No need for a loop, just get the function to schedule itself again.
My understanding is that what you're trying to do is the equivalent of Thread.sleep(5000) in a language like Java or C#. That functionality does not exist in JavaScript. If you want to do something some amount of time after your function's execution, put it in a timeout, but one way or another, that first function will still complete in the same frame unless you're performing an enormous amount of work.
Currently, your code is setting a timeout on sendit() a practically-infinite number of times before it returns. Since JavaScript is single threaded, even if 20 seconds passed, it still wouldn't have finished your function and couldn't start looking up timeouts it needs to process. What you should be doing is something like having the inside of the timeout set another timeout, and remove the enclosing while(true). That could allow for infinite, periodic behavior as I think you're looking for.
I'm trying to create a new scheduled report and I've one doubt about it: How can I create a script on it with a loop that runs a function every 10 seconds? Something like:
var value = 1;
while(value > 0){
setTimeout(function(){myFunction()},10000);
value = value -1;
}
When I just run my report into the report studio (without schedule) this script executes successfully, but after the schedule it doesn't work anymore. Someone know why is this happening or have any other idea?
Thanks in advance.
If you want to keep the same structure, you can use setTimeout to make it slightly recursive:
var repeatedFunction = function(){
// Do something
setTimeout(repeatedFunction, 10 * 1000);
};
but you're better off using setInterval:
setInterval(function(){
// do something
}, 10 * 1000);
and if you need to cancel it, store the interval:
var repeatedFunction = setInterval(function(){
// do something
}, 10 * 1000);
// .. something happened; need to cancel
clearTimeout(repeatedFunction);
Use setInterval instead of setTimeout.
Also your while loop is not needed.
Just use this instead:
setInterval(myFunction, 10000);
I have a little script that runs a simulation, of which I want to render the results 'live':
for ( i < simulation steps ) {
do_simulation();
render_with_flot();
}
I noticed that the plot only gets rendered after the last step.
Is there a way to 'suspend' javascript somehow to allow the rendering to run after each iteration?
Or is there a way to make flot run synchronously?
Or do I need to set my own timeouts for each iteration of the for-loop? This seems like kind of a hassle.
Depends how fast it needs to run, but the best way would be to use SetInterval
Pseudocode / hand-written-javascript-that-probably-doesnt-run:
var PerformedSteps;
var Interval;
PerformedSteps = 0;
Interval = setInterval(work, 1000/60); //60 times/second
function work()
{
PerformedSteps++;
if (PerformedSteps == simulation_steps)
{
clearInterval(Interval);
return;
}
do_simulation();
render_with_flot();
}
As an alternative to #PhonicUK's solution, you could do a setTimeout() at the end of work() to schedule the next call to work(), giving the rendering a chance to happen & not tying yourself to any particular refresh rate.
I'm trying to find a way to stop a function at a certain point until something does not have a specific class anymore. I cannot change the place where this class is being assigned and removed because it's a plugin.
I was thinking of doing something like this
function DoSomething() {
while ($('div.divControl').hasClass('playing'))
{
//Wait here
}
};
Is this the correct way to go?
This will block so the element will never be changed, as no other code will execute.
What you need to use is an interval:
var interval = setInterval(DoSomething, 500);
function DoSomething() {
if ($('div.divControl').hasClass('playing'))
{
// Do something
clearInterval(interval);
}
};
This will execute the function every half second. The interval will be cancelled after the function succeeds.
No, that will just hang the browser as it goes into an infinite loop.
Your best bet (as best I can think at the moment anyhow) is to do a setTimeout on the function and have it check to see if it your div still has the class every quarter of a second or so.
Still, not nice at all =[
I'm working on ui tabs built using jQuery. Everything works except for one issue - I did a setInterval that runs a function that does a trigger("click") so that it goes to the next tab after 5000 miliseconds. It runs through each tab fine, the issue is that if the user manually clicks on a tab, the timer for the setInterval does not restart back at 0. For example if a user were to start on tab1 at 0 miliseconds and clicks on tab2 at 2000 miliseconds, the setInterval doesn't go back to 0, it would start at 2000 and run to 5000 miliseconds and would subsequently goto tab3. I understand why it's happening, I just wonder if there were a way to restart the setInterval timing without having to do a clearInterval() and creating an entirely new setInterval(). Any insight would be appreciated.
Update
Thanks for the replies - The reason I was trying to avoid using clearInterval was because I was having issues of how to write the code in a way where the clearInterval would stop the setInterval completely. The code is setup to track whenever a user has clicked a tab. The problem is the auto change function utilizes trigger('click'), so it runs the clearInterval function I wrote also when the tabs auto-change. It seems to run fairly fine on its own, but once the user starts clicking on tabs, the setInterval behaves unusually and switches tabs unpredictably. I suspect what is happening is that several setIntervals are running at once... Here's the code (If you haven't guessed it already, I'm pretty new at javascript/jquery). I've commented out parts so that it's functional, but it still doesn't function as I intended (from first post).
// auto change tabs
if( options.interval ) {
function timerCom() {
if( !$(".controller").hasClass('paused') ) {
var i = $(".tab-current > a").attr("rel");
//alert(i);
if( i == 3 ) {i = 0};
$container
.find('a')
.eq(i)
.trigger('click');
}
}
//$("#promo-items > li > a").click(function () {
//var timer;
//if( timer != null ) {clearInterval(timer);}
timer = setInterval(timerCom, options.interval);
//});
}
No, there is no way to restart a timer set by setInterval without clearing the timer.
You can't really alter intervals or timeouts, only clear them. That said it should be a simple thing to create a function that clears the interval, and then starts a new but identical one immediately with a fresh time value.
var intervalID;
var resetTimer = function() {
if (intervalID) { clearInterval(intervalID) };
intervalID = setInterval(function() {
console.log('doing stuff!');
}, 5000);
};
timer = setInterval(function() {
timerCom();
}, options.interval);
I know this post is well over 2 years old, but I ran into a similar problem just now, and I found a solution.
I was writing an image scroller that would automatically shift to the next image after a set amount of time, and whenever I clicked the navigation buttons, the transitions moved double-time.
Here's my solution:
Make the interval variable (timer in your case) somewhat global.
i.e. in the options section (assuming it was defined earlier, and then later assigned), add a null timer variable.
var options = {
'interval',
//Other variables
'timer',
};
Then, call clearInterval twice when you handle the click event.
$("#promo-items > li > a").click(function () {
if( options.timer != null ) {
clearInterval(options.timer);
clearInterval(options.timer);
}
options.timer = setInterval(timerCom, options.interval);
});
Worked like a charm for me.
Again, sorry if this is wayyyy too late.