IE6 7 select option设置disabled无效

系统单据的一个分类需要禁用（不是删除）,做单据的表单是用的下拉列表，马上就想到了 把那个option disabled.

function diableSelectItem(id,v){
         var el = document.getElementById(id);
         for(var i=0,j = el.options.length;i<j;i++){
             if(el.options[i].value == v){ el.options[i].disabled=true;break;}
         }
 }

OK，运行，发现选项没有显示灰色，仍然可用。！！！代码没问题啊，怎么办？ 突发奇想 拿个IE8来试试，竟然禁用了。NND 是IE的问题
怎么办，有问题，找google 发现 Select, Option, Disabled And The JavaScript Solution
有老外已经搞定了。贴代码：

/****************************************************************
* Author:    Alistair Lattimore
* Website:    http://www.lattimore.id.au/
* Contact:    http://www.lattimore.id.au/contact/
*            Errors, suggestions or comments
* Date:        30 June 2005
* Version:    1.0
* Purpose:    Emulate the disabled attributte for the <option>
*            element in Internet Explorer.
* Use:        You are free to use this script in non-commercial
*            applications. You are however required to leave
*            this comment at the top of this file.
*
*            I'd love an email if you find a use for it on your
*            site, though not required.
****************************************************************/

window.onload = function() {
    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";
        }
    }
}

模拟了disabled的效果，改变文本颜色，当一个选项有 disabled属性，就让select元素选择索引回滚默认值

另附上判断IE版本的js代码 来自 司徒正美

var ie = (function() {
          var v = 3, div = document.createElement('div'), a = div.all || [];
          while (div.innerHTML = '<!--[if gt IE '+(++v)+']><br><![endif]-->', a[0]);
          return v > 4 ? v : !v;
        }());