get SHA1 hash

in websockets you need to convert string to sha1 then to hex then base64 this hex
I was doing something like:

function hexEncode(str) {
    var x = [];
    for (var i = 0; i < str.length; i += 2) {
        x.push(String.fromCharCode("0x" + str.substr(i, 2)));
    }
    return btoa(x.join(""));
}