JS正则表达式 替换括号,尖括号等

function toTxt(str) {
    var RexStr = /\<|\>|\"|\‘|\&/g
    str = str.replace(RexStr, function(MatchStr) {
        switch (MatchStr) {
        case "<":
            return "<";
            break;
        case ">":
            return ">";
            break;
        case "\"":
            return """;
            break;
        case "‘":
            return "‘";
            break;
        case "&":
            return "&";
            break;
        default:
            break;
        }
    })
    return str;
}