模仿password輸入框

function hiddenPass(event) {
    var password0 = document.getElementById("password0");
    var password1 = document.getElementById("password1");

    if (event.keyCode == 13) {
    }

    var keycode;
    if (window.event) { // IE
        keycode = event.keyCode
    } else if (event.which) { // Netscape/Firefox/Opera
        keycode = event.which
    }
    var keychar = String.fromCharCode(keycode);
    password1.value = password1.value + keychar;
    password1.value = password1.value.substring(0, password0.length);
}

function clearPass(){
    $("#password0").val("");
    $("#password1").val("");
}

<li class="ba"><label>密  碼：</label>
    <input type="text" id="password0"
           onfocus="javascript:clearPass();"
           onkeyup="this.value=this.value.replace(/./g,'*')"
           onkeypress="javascript:hiddenPass(event);"/>
    <input type="hidden" id="password1" name="password1"/>
</li>