字符串大小写转换

//大写转小写
function manualLowercase(s) {
    s.replace(/[A-Z]/g, function(ch) {
        return String.fromCharCode(ch.charCodeAt(0) | 32);
    });
}
//小写转大写
function manualUppercase(s) {
    s.replace(/[a-z]/g, function(ch) {
        return String.fromCharCode(ch.charCodeAt(0) & ~32);
    });
}