Uncaught TypeError: Cannot read property 'length' of undefined,代碼如下。為什么71行的length會(huì)undefined
// JavaScript Document
var window_width=1024;
var window_height=768;
var radius_=8;
var margin_top=60;
var margin_left=30;
const endTime=new Date(2016,5,14,18,30,50);
var curShowTimeSeconds=0;
var balls = [];
const colors = ["#33B5E5","#0099CC","#AA66CC","#9933CC","#99CC00","#669900","#FFBB33","#FF8800","#FF4444","#CC0000"];
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 getCurrentShowTimeSeconds(){
var curTime=new Date();
var ret=endTime.getTime()-curTime.getTime();
ret=Math.round(ret/1000);
return ret>=0?ret:0;
}
function update(){
var nextShowTimeSeconds=getCurrentShowTimeSeconds();
var nextHours=parseInt(nextShowTimeSeconds/(60*60)%24)? ;
var nextMinutes =? parseInt(nextShowTimeSeconds/60%60)? ;
var nextSeconds= parseInt(nextShowTimeSeconds%60);
var curHours = parseInt( curShowTimeSeconds / 3600);
var curMinutes = parseInt( (curShowTimeSeconds - curHours * 3600)/60 );
var curSeconds = curShowTimeSeconds % 60;
if(nextSeconds!=curSeconds){
? if( parseInt(curHours/10) != parseInt(nextHours/10) ){
??????????? addBalls( margin_left + 0 ,margin_top , parseInt(curHours/10) );
??????? }
??????? if( parseInt(curHours%10) != parseInt(nextHours%10) ){
??????????? addBalls(? margin_left + 15*(radius_+1) ,margin_top , parseInt(curHours/10) );
??????? }
??????? if( parseInt(curMinutes/10) != parseInt(nextMinutes/10) ){
??????????? addBalls( margin_left+ 39*(radius_+1) ,margin_top, parseInt(curMinutes/10) );
??????? }
??????? if( parseInt(curMinutes%10) != parseInt(nextMinutes%10) ){
??????????? addBalls(? margin_left + 54*(radius_+1) , margin_top , parseInt(curMinutes%10) );
??????? }
??????? if( parseInt(curSeconds/10) != parseInt(nextSeconds/10) ){
??????????? addBalls(? margin_left + 78*(radius_+1) ,margin_top , parseInt(curSeconds/10) );
??????? }
??????? if( parseInt(curSeconds%10) != parseInt(nextSeconds%10) ){
??????????? addBalls(? margin_left+ 93*(radius_+1) ,margin_top , parseInt(nextSeconds%10) );
??????? }
curShowTimeSeconds=nextShowTimeSeconds;}
}
function updateBalls(){
for(var i=0;i<balls.length;i++){
balls[i].x+=balls[i].vx;
balls[i].y+=ball[i].vy;
ball[i].vy+=ball[i].g;
if(balls[i].y>=window_height-radius_){
balls[i].y=window_height-radius_;
balls[i].vy=-balls[i].vy*0.75;
}
}
}
function addBalls(x,y,num){
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){
?? ?var aBall={
?? ?x:x+j*2(radius_+1)+(radius_+1),
?? ?y:y+i*2*(radius_+1)+(radius_+1),
?? ?g:1.5+Math.random(),
?? ?vx:Math.pow(-1,Math.ceil(Math.random()*1000))*4,
?? ?vy:-5,
?? ?color:colors[Math.floor(Math.random()*color.length)]
?? ?}
?? ? balls.push( aBall );
?? ?}
}
}
}
function render(cxt){
?? ? cxt.clearRect(0,0,window_width, window_height);
var hours=parseInt(curShowTimeSeconds/(60*60)%24);
var minutes =? parseInt(curShowTimeSeconds/60%60);
var seconds= parseInt(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);
for( var i = 0 ; i < balls.length ; i ++ ){
??????? cxt.fillStyle=balls[i].color;
??????? cxt.beginPath();
??????? cxt.arc( balls[i].x , balls[i].y , RADIUS , 0 , 2*Math.PI , true );
??????? cxt.closePath();
??????? cxt.fill();
??? }
}
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();
?? ?}
}}
}
2017-02-15
怎么解決?
2016-05-14
已經(jīng)解決