function redraw(){ canvas.width = canvas.width; // Clears the canvas context.strokeStyle = "#df4b26"; context.lineJoin = "round"; context.lineWidth = 5; for(var i=0; i < clickX.length; i++) { context.beginPath(); if(clickDrag[i] && i){//当是拖动而且i!=0时,从上一个点开始画线。 context.moveTo(clickX[i-1], clickY[i-1]); }else{ context.moveTo(clickX[i]-1, clickY[i]); } context.lineTo(clickX[i], clickY[i]); context.closePath(); context.stroke(); } }