我第二行一致报错
var chess=document.getElementById('chess');
var context=chess.getContext('2d');
context.strokeStyle='#BFBFBF';
for(var i=0;i<15;i++){
context.moveTo(15+1*30,15);
context.lineTo(15+1*30,15);
context.stroke();
context.moveTo(15,15+1*30);
context.lineTo(15,15+1*30);
context.stroke();
}
var chess=document.getElementById('chess');
var context=chess.getContext('2d');
context.strokeStyle='#BFBFBF';
for(var i=0;i<15;i++){
context.moveTo(15+1*30,15);
context.lineTo(15+1*30,15);
context.stroke();
context.moveTo(15,15+1*30);
context.lineTo(15,15+1*30);
context.stroke();
}