js中hex16进制颜色与rgb互转

function hexToRgba(hex, opacity) { 
    return "rgba(" + parseInt("0x" + hex.slice(1, 3)) + "," + parseInt("0x" + hex.slice(3, 5)) + "," + parseInt("0x" + hex.slice(5, 7)) + "," + opacity + ")"; 
}

　　

function rgbToHex(r, g, b) {
    return ((r << 16) | (g << 8) | b).toString(16); 
}