解決ie6,ie7的select option disabled沒有作用的問題 Select, Option, Disabled And The JavaScript Solution In IE7, IE6, IE5.5

解決方案:
http://www.lattimore.id.au/2005/07/01/select-option-disabled-and-the-javascript-solution/

下載js檔, 並include到頁面即可, 作法是把頁面的select element找出來, 判斷有disabled的option就變顏色且不可選擇
http://www.lattimore.id.au/files/examples/select-option-disabled-emulation.js

因為只有在ie7以下的版本有問題, 其他瀏覽器沒問題, 所以我改寫了一下

if (navigator.appVersion.indexOf("MSIE 5.5") >= 0 || navigator.appVersion.indexOf("MSIE 6.0") >= 0 || navigator.appVersion.indexOf("MSIE 7.0") >= 0) {
           window.onload = ReloadSelectElement;
       }
       function ReloadSelectElement() {
           if (document.getElementsByTagName) {
               var s = document.getElementsByTagName("select");
               if (s.length > 0) {
                   window.select_current = new Array();
                   for (var i = 0, select; select = s[i]; i++) {
                       select.onfocus = function() { window.select_current[this.id] = this.selectedIndex; }
                       select.onchange = function() { restore(this); }
                       emulate(select);
                   }
               }
           }
       }
       function restore(e) {
           if (e.options[e.selectedIndex].disabled) {
               e.selectedIndex = window.select_current[e.id];
           }
       }
       function emulate(e) {
           for (var i = 0, option; option = e.options[i]; i++) {
               if (option.disabled) {
                   option.style.color = "graytext";
               }
               else {
                   option.style.color = "menutext";
               }
           }
       }