html5清除画布代码是什么

function clearCanvas<span style="font-family: Verdana, Arial, 宋体;">()</span>
{
    var c=document.getElementById("myCanvas");
    var cxt=c.getContext("2d");
    c.height=c.height;
}

function clearCanvas()
{
var c=document.getElementById("myCanvas");
var cxt=c.getContext("2d");
cxt.clearRect(0,0,c.width,c.height);
}

function clearCanvas()
{
var c=document.getElementById("myCanvas");
var cxt=c.getContext("2d");
cxt.fillStyle="#000000";
cxt.beginPath();
cxt.fillRect(0,0,c.width,c.height);
cxt.closePath();
}