/**
?*?Created?by?yzsoft?on?2015/7/24.
?*/

var?WINDOW_WIDTH?=?1024;
var?WINDOW_HEIGHT?=?768;
var?RADIUS?=?8;
var?MARGIN_TOP?=?60;
var?MARGIN_LEFT?=?30;

const?endTime?=?new?Date(2014,7,25,18,47,52);
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();
????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(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();
????????????}
????????}
????}
}

為什么修改了時間頁面就沒有任何東西了呢