/***********************************************************************
** Author: 	Truly
** Web:		http://Truly.cnblogs.com
** Date:	2006.11.10
** Desc:	模拟select控件，实现自定义下拉图片和自定义边框颜色
**			initSelect(id,width,height)进行初始化，
**			setSelectByIndex(id,index)进行某项的选中
**			body 的 onclick=HideSel(event),onload=initSelect('下拉框select的id'),兼容IE和FireFox
** Note:	注意修改<img src=''>中的下拉图片地址
***********************************************************************/
var imgPath = "css/darrow.jpg";
var blOut = true;
var nowOpenedSelectBox = null;
function gid(id){	return document.getElementById?document.getElementById(id):null;}
function initSelect(id, width, height)
{
    var sel = gid(id);
    var a = sel.options;
	var oTable,oTBody, oRow, oCell,oSelect;
	
	if(!gid('O' + id )) {
	    var strWidth = "";
	    if(width != null)	strWidth=width+"px";
	    else strWidth = gid(id).offsetWidth + "px";
	    
	    var strWidth2 = parseInt(strWidth) - 22 + 'px';
	    
		var arr = new Array(a.length);
		for (var i=0,j=a.length;i<j; i++)
		{
			arr[i] = "<tr><td nowrap title='" + a[i].text + "' value='" + a[i].value + "'>" + HtmlEncode(a[i].text) + "</td></tr>";
		}
		// 虽然用insertAdjacentElement可以获得更好的性能，但是由于如果用insertAdjacentElement势必多次使用innerHTML处理，因此就全局来看这里调用1次insertAdjacentElement，反而取得更好的效果。
	    sel.insertAdjacentHTML("beforeBegin","<table border=0 cellpadding=0 cellspacing=0 width='" + strWidth + "'><tr><td><table width=\"100%\" cellpadding=0 cellspacing=0 border=0 class='sel_normal' onclick=\"showHide('O" + id + "')\" onmouseout=\"blOut = false;\">\
	    <tr bgcolor=white>\
		    <td style='padding-left:3px;padding-right:3px;' nowrap><input type=\"hidden\" name=\"C_O" + id + "\" id=\"C_O" + id + "\"><DIV class='fixedWidth' style='padding-top:3px;width:" + strWidth2 + "' id=\"S_O" + id + "\">下拉选项</DIV></td>\
		    <td width=\"15\"><img src='" + imgPath + "' /></td>\
	    </tr>\
	    </table></td><tr><td><div id=\"O" + id + "\" class=\"select\" onselectstart=\"return false\" onmouseover=\"HoverOptions(event);\" onmouseout=\"OutOptions(event);\" onclick=\"ClickOptions(event, 'O" + id + "');\">\
		    <table cellsapcing=\"0\" cellspadding=\"3\" border=\"0\" width=100%>\
		    <tbody>" + arr.join('') + "</tbody>\
		    </table>\
	    </div></td></tr></tbody></table>");

	}
	else
	{
	    oSelect = gid('O' + id );
	    var arr = new Array(a.length);
		for (var i=0,j=a.length;i<j; i++)
		{
			arr[i] = "<tr><td nowrap title='" + a[i].text + "' value='" + a[i].value + "'>" + a[i].text + "</td></tr>";
		}
		oSelect.parentNode.innerHTML = "<div id=\"O" + id + "\" style=\"position:absolute;\" onselectstart=\"return false\" onmouseover=\"HoverOptions(event);\" onmouseout=\"OutOptions(event);\" onclick=\"ClickOptions(event, 'O" + id + "');\">\
		    <table cellsapcing=\"0\" cellspadding=\"3\" border=\"0\" width=100%>\
		    <tbody>" + arr.join('') + "</tbody>\
		    </table></div>";
	}
	
    oSelect = gid("O"+id);
    
    sel.style.display='none';
    
    // 如果超过8项，下拉框出现滚动条
    if(a.length > 8)
    {
        oSelect.style.overflowY = 'scroll';
        oSelect.style.height = 182;
    }
    else
    {
        oSelect.style.overflowY = 'hidden';
        oSelect.style.height = null;
    }
	
	// 加载原始下拉框的选中项
	if(sel.selectedIndex > -1)
	{
	    setSelectByIndex(id, sel.selectedIndex);
	}
	else if(sel.options.length > 0)
	{
	    setSelectByIndex(id, 0);
	}

}

function showHide(id){

    HideSel();
	blOut = true;
	nowOpenedSelectBox = id;
	var sh={block:"none",none:"block"};
	if(gid(id).style.display=='') gid(id).style.display='none';
	gid(id).style.display=sh[gid(id).style.display];
}

function HideSel(event)
{
	if(!blOut && nowOpenedSelectBox && gid(nowOpenedSelectBox))
		gid(nowOpenedSelectBox).style.display = 'none';
}
function HoverOptions(event)
{
	blOut = true;
	var obj = event.srcElement ? event.srcElement : event.target;
	if(obj.tagName=="TD"){
	    obj.className='option_hover';
	}
}
function OutOptions(event)
{
	blOut = false;
	var obj = event.srcElement ? event.srcElement : event.target;
	if(obj.tagName=="TD"){
	    obj.className='option_out';
	} 
}
function ClickOptions(event, id)
{
	var obj = event.srcElement ? event.srcElement : event.target;
	if(obj.tagName=="TD"){
        showHide(obj.parentNode.parentNode.parentNode.parentNode.id);
        gid('S_'+id).innerHTML=obj.innerHTML;
        gid('C_'+id).value=obj.value;

        var sourceObj = gid(id.substr(1));
        sourceObj.selectedIndex = obj.parentNode.rowIndex;
        if (sourceObj.onchange) sourceObj.onchange();
	} 
}
// 根据指定索引选中下拉框
function setSelectByIndex(id,index)
{
    if(index <0) index = 0;
    gid(id).selectedIndex = index;
    gid('S_O'+id).innerHTML=gid(id).options[index].text;
    gid('C_O'+id).value=gid(id).value;
    
    gid(id).fireEvent('onchange');
}
// 根据指定值选中下拉框
function setSelectByValue(id, value) {
    setSelectByIndex(id, getIndex(id, value));
    gid(id).fireEvent('onchange');
}
function getIndex(id, value)
{
	var selectBox = gid(id)
    var arOptions = selectBox.options;
    var strCompare = new String(value).toLowerCase();
    var intCompareLen = strCompare.length;
    var i, j; 
 
    for (i = 0; i < arOptions.length; i++) {
        if (strCompare == arOptions[i].value.substring(0,intCompareLen).toLowerCase()) {  
            for(j = 0; j < arOptions.length; j++) 
                ; 
            return i;
            break;
            }
    }
}
// 隐藏和显示某项
function HideItem(id, index)
{
    gid("O" + id).childNodes[0].rows[index].style.display = 'none';    
}
function ShowItem(id, index)
{
    gid("O" + id).childNodes[0].rows[index].style.display = 'block';    
}
function HtmlEncode(text)
{
	var re = {'<':'&lt;','>':'&gt;','&':'&amp;','"':'&quot;'};
	for (i in re) text = text.replace(new RegExp(i,'g'), re[i]);
	return text;
}