js中RGB转hex

var rgb = '220,20,60';
alert(rgb2hex(rgb));
//将RGB转换成#HEX
function rgb2hex(rgb) {
var reg=/(\d{1,3}),(\d{1,3}),(\d{1,3})/;
var arr=reg.exec(rgb);

function hex(x) {
return ("0" + parseInt(x).toString(16)).slice(-2);
}
var _hex="#" + hex(arr[1]) + hex(arr[2]) + hex(arr[3]);
return _hex.toUpperCase();
}