Making a javascript string sql friendly

It turns out that mysql_real_escape_string() is pretty trivial. According to the documentation:

mysql_real_escape_string() calls MySQL's library function mysql_real_escape_string, which prepends backslashes to the following characters: \x00, \n, \r, \, ', " and \x1a.

Sounds pretty simple, actually. You could do something like this:

function mysql_real_escape_string (str) {
    return str.replace(/[\0\x08\x09\x1a\n\r"'\\\%]/g, function (char) {
        switch (char) {
            case "\0":
                return "\\0";
            case "\x08":
                return "\\b";
            case "\x09":
                return "\\t";
            case "\x1a":
                return "\\z";
            case "\n":
                return "\\n";
            case "\r":
                return "\\r";
            case "\"":
            case "'":
            case "\\":
            case "%":
                return "\\"+char; // prepends a backslash to backslash, percent,
                                  // and double/single quotes
            default:
                return char;
        }
    });
}

NOTE: I haven't run this through any sort of unit test or security test, but it does seem to work -- and, just as an added bonus, it escapes tabs, backspaces, and '%' so it can also be used in LIKE queries, as per OWASP's recommendations (unlike the PHP original).

I do know that mysql_real_escape_string() is character-set-aware, but I'm not sure what benefit that adds.

There's a good discussion of these issues over here.

Learnt the hard way that passing numbers to this function causes the whole process it is used in to die quietly. So I add a little test:

function mysql_real_escape_string (str) {
    if (typeof str != 'string')
        return str;

    return str.replace(/[\0\x08\x09\x1a\n\r"'\\\%]/g, function (char) {
        switch (char) {
            case "\0":
                return "\\0";
            case "\x08":
                return "\\b";
            case "\x09":
                return "\\t";
            case "\x1a":
                return "\\z";
            case "\n":
                return "\\n";
            case "\r":
                return "\\r";
            case "\"":
            case "'":
            case "\\":
            case "%":
                return "\\"+char; // prepends a backslash to backslash, percent,
                                  // and double/single quotes
        }
    });
}