沒有效果!nextShowTimeSeconds和curShowTimeSeconds都是從getCurrentShowTimeSenconds()獲取! 后面比較nextSeconds 和curSeconds那就是相等的啊; 那個 if( nextSeconds! = curSeconds ){ ? ? ? ?curShowTimeSeconds = nextShowTimeSeconds; ? ?} 就不會執(zhí)行,所以沒有效果! 改成 nextSeconds = curSeconds,就有效果了! 為什么啊!求解

/**
* Created by Administrator on 2017/3/9 0009.
*/
var WINDOW_WIDTH=1024;
var WINDOW_HEIGHT=768;
var RADIUS=8;
var MARGIN_TOP=60;
var MARGIN_LEFT=30;
const endTime=new Date("2017/3/13,12:45:45");
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=getCurrentShowTimeSenconds();

? ?setInterval(function(){
? ? ? ?render(context);
? ? ? ?update();

? ?},1000)

};

function getCurrentShowTimeSenconds(){
? ?var curTime=new Date();
? ?var ret=endTime.getTime()-curTime.getTime();
? ?ret=Math.round(ret/1000);
? ?return ret>=0? ret:0;
}

function update(){
? ?var nextShowTimeSeconds=getCurrentShowTimeSenconds();

? ?var nextHours=parseInt(curShowTimeSeconds/3600);
? ?var nextminutes=parseInt(curShowTimeSeconds-nextHours*3600)/60;
? ?var nextSeconds=curShowTimeSeconds%60;

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

? ?if( nextSeconds = curSeconds ){
? ? ? ?console.log(curSeconds+"和"+nextSeconds)
? ? ? ?console.log(curShowTimeSeconds+"和"+nextShowTimeSeconds)
? ? ? ?curShowTimeSeconds = nextShowTimeSeconds;

? ?}
};

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+79*(RADIUS+1),MARGIN_TOP,parseInt(seconds/10),cxt);
? ?renderDigit(MARGIN_LEFT+94*(RADIUS+1),MARGIN_TOP,parseInt(seconds%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();
? ? ? ? ? ?}
? ? ? ?}
? ?}
}