setinterval | 易学教程

How to notify a component that it needs to update

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问题 As you can see in the code below, I check every 100ms (using setInterval ) whether a change has been made to convertProgress , and if so, the component needs to update. class TradingThing extends React.Component { componentDidMount() { const { convertProgress, setConvertProgress } = this.props.store; // mobx store this.interval = setInterval(() => { if(convertProgress < 100) { setConvertProgress(Math.min(convertProgress + 5, 100)); } , 100); } componentWillUnmount() { clearInterval(this

JavaScript HTML5-Canvas - Drawing an Arc with SetInterval Causes Jagged Edges

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问题 I'm trying to draw a donut chart, and so far I've been successful. The problem is that when trying to animate the arc by combining stroke() with setInterval() , it works, but it does not look smooth, and produces jagged edges. I tried using clearRect() to clear the canvas after the animation was done and re-add the final version of the animation, but I must have been using clearRect() wrong, because it did nothing. If you have any ideas on how to get this looking good, I'd really appreciate

setInterval and setTimeout

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问题 var myTimer = setInterval(function(){ var eleID = ''; var delayTimer = ''; $('#hp-fcas li').each(function(i) { eleID = $(this).attr('id'); delayedTrigger( $('#'+eleID + ' a'), 7000*i); }); function delayedTrigger(elem, delay){ setTimeout(function(){ $(elem).trigger('click'); }, delay ); } }, 21000); $(".play").click(function(){ clearTimeout(); clearInterval(myTimer); }); The first interval is 21 seconds, of the first instance. the 2nd interval is 3 7-second instances (what I want). I'm trying

setInterval and setTimeout

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setInterval and setTimeout

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Nativescript getViewById not updating for count down

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问题 So, i am using the timer that i asked about in this question as a count down: How to stop timer.setinterval with a tap event or leaving page in nativescript The counter works, all this while i have been using console.log to check if it works and yes it does but i want to make it appear in the xml for the user of that app to see. But the count does not update in the xml. Here's the code for the view: <Page xmlns="http://schemas.nativescript.org/tns.xsd" loaded="pageLoaded" navigatedTo=

clearInterval,setInterval,clearTimeout,setTimeout

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setInterval("f()",1000) 每隔1秒就执行一次f() clearInterval 关闭clearInterval setTimeout("f()",1000) 1秒后执行f(),只执行一次 clearTimeout 关闭setTimeout 1.简单版应用html代码 <html> <head> <script type="text/javascript"> var c=0 var t function timedCount() { document.getElementById('txt').value=c c=c+1 t=setTimeout("timedCount()",1000) } function stopCount() { clearTimeout(t) } </script> </head> <body> <form> <input type="button" value="Start count!" onClick="timedCount()"> <input type="text" id="txt"> <input type="button" value="Stop count!" onClick="stopCount()"> </form> </body> </html> 2.文字上下翻滚html代码（无缺陷） <script type=

使用setTimeout模拟setInterval效果

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　　由于现在部分浏览器基于对系统性能的优化，在使用setInterval的时候，在页面没有获得关注的状态，浏览器可以会自动将setInterval终端，等到该页面重新获得关注时再开启。这样就会使得一些基于setInterval的定时效果出现意想不到的问题；　　解决的办法就是使用setTimeout来模拟setInterval的效果。　　具体实现过程如下： var i = 0;function time(){ //每隔1秒让++i console.log(++i); setTimeout(time,1000); } time(); //执行time函数 btn.onclick = function(){ time = null; //重写time函数，从而起到关闭定时器的效果 } 来源： https://www.cnblogs.com/hellobajie/p/5558417.html

setTimeout 和 setInterval 的区别

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setTimeout (表达式,延时时间) setInterval(表达式,交互时间) 延时时间/交互时间是以豪秒为单位的(1000ms=1s) setTimeout 在执行时,是在载入后延迟指定时间后,去执行一次表达式,仅执行一次 setInterval 在执行时,它从载入后,每隔指定的时间就执行一次表达式 set Timeout 也可以实现象setInterval一样的功能 set Timeout: <script language="javascript"> var i; i=0; function reloop() { i=i+1; alert(String(i)); setTimeout("reloop()",1000); } reloop(); </script> setInterval: <script language="javascript"> var i; i=0; function reloop() { i=i+1; alert(String(i)); } setInterval("reloop()",1000); </script> window对象有两个主要的定时方法，分别是setTimeout 和 setInteval 他们的语法基本上相同，但是完成的功能取有区别。　　setTimeout方法是定时程序，也就是在什么时间以后干什么。干完了就拉倒。　

(二)学习JavaScript之setInterval和clearInterval方法

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参考： http://www.w3school.com.cn/jsref/met_win_setinterval.asp HTML DOM Window 对象定义和用法 setInterval() 方法可按照指定的周期（以毫秒计）来调用函数或计算表达式。 setInterval() 方法会不停地调用函数，直到 clearInterval() 被调用或窗口被关闭。由 setInterval() 返回的 ID 值可用作 clearInterval() 方法的参数。语法 setInterval(code,millisec[,"lang"]) 参数　　　　描述 code 　　必需。要调用的函数或要执行的代码串。 millisec 必须。周期性执行或调用 code 之间的时间间隔，以毫秒计。返回值一个可以传递给 Window.clearInterval() 从而取消对 code 的周期性执行的值。参考： http://www.w3school.com.cn/jsref/met_win_clearinterval.asp HTML DOM Window 对象定义和用法 clearInterval() 方法可取消由 setInterval() 设置的 timeout。 clearInterval() 方法的参数必须是由 setInterval() 返回的 ID 值。语法