我试图在Canvas上绘制两条平行线,但后者的属性似乎覆盖了前者。请提出可能出错的地方:functiondraw(){varcanvas=document.getElementById('canvas');varctx=canvas.getContext('2d');//drawa10pixgreenlinectx.strokeStyle='#00cc00';ctx.lineWidth=10;ctx.moveTo(100,0);ctx.lineTo(100,1000);ctx.stroke();//drawa20pixredlinectx.strokeStyle='#cc0000';c