为什么时间是十秒刷新一次的

Question

/**
* Created by Administrator on 2016/5/25.
*/
var WINDOW_WIDTH=1200;
var WINDOW_HEIGHT=600;
var RADIUS=8;
var MARGIN_LEFT=30;
var MARGIN_TOP=60;
const endTime=new Date(2016,4,31,21,36,36);
var curShowTimeSeconds=0;

window.onload=function(){
   var canvas=document.getElementById('canvas');
   var context=canvas.getContext("2d");

   canvas.width=WINDOW_WIDTH;
   canvas.height=WINDOW_HEIGHT;

   curShowTimeSeconds=getCurrentShowTimeSeconds();
   //render(context);
   setInterval(
       function () {
           render(context);
           update();
       }
       ,
       50
   );
};
function update() {
   var nextShowTimeSeconds=getCurrentShowTimeSeconds();

   var nextHours=parseInt(nextShowTimeSeconds/3600);
   var nextMinutes=parseInt((nextShowTimeSeconds-nextHours*3600)/60);
   var nextSeconds=nextShowTimeSeconds%60;

   var curHours=parseInt(curShowTimeSeconds/3600);
   var curMinutes=parseInt((curShowTimeSeconds-curHours*3600)/60);
   var curSeconds=curShowTimeSeconds%60;

   if(nextSeconds!=curSeconds){
       curShowTimeSeconds=nextShowTimeSeconds;
   }
}
function getCurrentShowTimeSeconds() {
   var curTime=new Date();
   var ret=endTime.getTime()-curTime.getTime();
   ret=Math.round(ret/1000);

   return ret>=0?ret:0;
}
function render(cxt) {

   cxt.clearRect(0,0,WINDOW_WIDTH,WINDOW_HEIGHT);

   var hours=parseInt(curShowTimeSeconds/3600);
   var minutes=parseInt((curShowTimeSeconds-hours*3600)/60);
   var seconds=curShowTimeSeconds%60;

   renderDigit(MARGIN_LEFT,MARGIN_TOP,parseInt(hours/10),cxt);
   renderDigit(MARGIN_LEFT+15*(RADIUS+1),MARGIN_TOP,parseInt(hours%10),cxt);
   renderDigit(MARGIN_LEFT+30*(RADIUS+1),MARGIN_TOP,10,cxt);
   renderDigit(MARGIN_LEFT+39*(RADIUS+1),MARGIN_TOP,parseInt(minutes/10),cxt);
   renderDigit(MARGIN_LEFT+54*(RADIUS+1),MARGIN_TOP,parseInt(minutes%10),cxt);
   renderDigit(MARGIN_LEFT+69*(RADIUS+1),MARGIN_TOP,10,cxt);
   renderDigit(MARGIN_LEFT+78*(RADIUS+1),MARGIN_TOP,parseInt(seconds/10),cxt);
   renderDigit(MARGIN_LEFT+93*(RADIUS+1),MARGIN_TOP,parseInt(minutes%10),cxt);
}

function renderDigit(x,y,num,cxt) {
   cxt.fillStyle="rgb(0,102,153)";

   for(var i=0;i<digit[num].length;i++)
       for(var j=0;j<digit[num][i].length;j++)
           if (digit[num][i][j] == 1) {
               cxt.beginPath();
               cxt.arc(x + j * 2 * (RADIUS + 1) + (RADIUS + 1), y + i * 2 * (RADIUS + 1) + (RADIUS + 1),
                   RADIUS, 0, 2 * Math.PI);
               cxt.closePath();

               cxt.fill();
           }
}

Answer 1

这个不就是 某个老师的时间倒数  很多小球掉落的教程吗? 怎么小白我感觉你没把全部代码放上来呢;印象中是有这么一段代码  setInterval ("update()",1000);我建议你如果是用sublimetext 软件编程你可以按CTRL +F  搜索setInterval 这样你就可以找到 setInterval ("XXX()",1000);的代码

Answer 2

对啊  但是还没写到小球那里   就写的时间改变的