form表单提交等待弹窗 屏蔽F5刷新

//关闭等待窗口
function closediv()
 {
    //Close Div
    document.body.removeChild(document.getElementById("bgDiv"));
    document.getElementById("msgDiv").removeChild(document.getElementById("msgTitle"));
    document.body.removeChild(document.getElementById("msgDiv"));
}
//显示等待窗口
function showdiv(str)
 {
    var msgw,
    msgh, bordercolor;
     msgw = 400; //提示窗口的宽度
    msgh= 100; //提示窗口的高度
    bordercolor= "#336699";
//提示窗口的边框颜色
    titlecolor = "#99CCFF";
//提示窗口的标题颜色
 
    var sWidth,
     sHeight;
    sWidth= window.screen.availWidth;
    sHeight= window.screen.availHeight;
    var bgObj= document.createElement("div");
     bgObj.setAttribute('id','bgDiv');bgObj.style.position= "absolute";
      bgObj.style.top= "0";
    bgObj.style.background = "#777";
    bgObj.style.filter= "progid:DXImageTransform.Microsoft.Alpha(style=3,opacity=25,finishOpacity=75";
    bgObj.style.opacity= "0.6";
    bgObj.style.left= "0";
    bgObj.style.width= sWidth + "px";
    bgObj.style.height= sHeight + "px";
    document.body.appendChild(bgObj);
    var msgObj= document.createElement("div")
    msgObj.setAttribute("id","msgDiv");
    msgObj.setAttribute("align","center");
    msgObj.style.position= "absolute";
    msgObj.style.background= "white";
    msgObj.style.font= "12px/1.6emVerdana, Geneva, Arial, Helvetica, sans-serif";
    msgObj.style.border = "1px solid " + bordercolor;
    msgObj.style.width= msgw + "px";
    msgObj.style.height= msgh + "px";
    msgObj.style.top= (document.documentElement.scrollTop + (sHeight - msgh) / 2) -150+ "px";
    msgObj.style.left= (sWidth - msgw) / 2-150 + "px";
    var title= document.createElement("h4");
    title.setAttribute("id","msgTitle");
    title.setAttribute("align","right");
    title.style.margin= "0";
    title.style.padding= "3px";
    title.style.background= bordercolor;
    title.style.filter= "progid:DXImageTransform.Microsoft.Alpha(startX=20,startY=20, finishX=100, finishY=100,style=1,opacity=75,finishOpacity=100);";
     title.style.opacity= "0.75";
    title.style.border= "1px solid " + bordercolor;
    title.style.height= "18px";
    title.style.font= "12px Verdana, Geneva, Arial, Helvetica, sans-serif";
  title.style.color= "white";
    //title.style.cursor= "pointer";
    //title.innerHTML= "关闭";
    //title.onclick= closediv;
    document.body.appendChild(msgObj);
    document.getElementById("msgDiv").appendChild(title);
    var txt= document.createElement("p");
    txt.style.margin= "1em 0"
    txt.setAttribute("id","msgTxt");
    txt.innerHTML= str;
    document.getElementById("msgDiv").appendChild(txt);
}
//屏蔽F5
document.onkeydown= mykeydown;
function mykeydown()
 {
    if (event.keyCode== 116) //屏蔽F5刷新键  
    {
        window.event.keyCode= 0;
        return false;
    }
}