var ctx = canvas.get(0).getContext("2d")；我就想知道这get（0）啥意思啊

Question

var ctx = canvas.get(0).getContext("2d");canvas.attr("width",$(window).get(0).innerWidth);canvas.attr("height",$(window).get(0).innerHeight);$(window).resize(resizeCanvas);function resizeCanvas(){     canvas.attr("width",$(window).get(0).innerWidth);     canvas.attr("height",$(window).get(0).innerHeight);     };

Answer 1

有多个canvas，取第一个