// 功能：打开遮挡层同时把下拉筐隐藏
var divId = "Div_Mask"
function openDivMask()
{	
    var divMask = document.getElementById(divId);
    if(!divMask){
        divMask = document.createElement("div");
        divMask.id = divId;	
        divMask.style.display = "block";
        divMask.style.top = divMask.style.left = divMask.style.margin = divMask.style.padding = "0px";
        var screenWidth;
	    var screenHeight;
	    if(document.body.scrollHeight<document.documentElement.offsetHeight){
		    screenHeight = document.documentElement.offsetHeight + "px";
	    }
	    else{
		    screenHeight = document.body.scrollHeight + "px";
	    }
	    if(document.body.scrollWidth<document.documentElement.offsetWidthh){
		    screenWidth = document.documentElement.offsetWidth + "px";
	    }
	    else{
		    screenWidth = document.body.scrollWidth + "px";
	    }	
	    divMask.style.width      = screenWidth;
	    divMask.style.height     = screenHeight;
	    divMask.style.position   = "absolute";
	    divMask.style.zIndex     = "99";
	    divMask.style.background = "#D3D3D3";
	    divMask.style.filter     = "alpha(opacity=50)";
	    divMask.style.opacity    = 50/100;
	    divMask.style.MozOpacity = 50/100;	
	    document.body.appendChild(divMask);	
	}else{
	    divMask.style.display = "block";
	}	
	//屏蔽SELECT
	var allselect = document.getElementsByTagName("select");
	if (allselect != null && allselect.length > 0){
	    for (var i=0; i<allselect.length; i++){ 
		    allselect[i].style.visibility = "hidden";
        }
    }
}
// 功能：关闭遮挡层同时把下拉筐显示
function closeDivMask()
{
	var objDialog = document.getElementById(divId);
	if (objDialog) objDialog.style.display = "none";
	
	var allselect = document.getElementsByTagName("select");
	if (allselect != null && allselect.length > 0){
	    for (var i=0; i<allselect.length; i++){
		    allselect[i].style.visibility = "visible";
        }
    }	     	           
}