canvas自适应移动端长宽,依赖于其父节点的大小的设置,将其父节点的样式和canvas样式设置如下便可:
<div style="height: 100%;width: 100%;margin: 0;padding: 0;"><canvas id="myCanvas" style=" height: 100%;width: 100%;margin: 0;padding: 0;display: block;"></canvas></div>