function hienthi(chon) {
    var nd = document.getElementById("khung_anh");
    var cao = document.getElementById("anh_to").offsetHeight/2;
           if (chon==1) {
            try {
                nd.style.left =  event.clientX + 5; 
                nd.style.top  =  event.clientY + document.documentElement.scrollTop + document.body.scrollTop - cao ; //parseInt(event.clientY + 5) + parseInt(document.body.scrollTop);
            }
            catch(e){
                try {
                    nd.style.left = event.clientX + window.scrollX + 'px';
                    nd.style.top =  event.clientY + window.scrollY + 'px';

                }
                catch(ex){}
            }
            nd.style.display = 'block';

        }
        else {
            nd.style.display = 'none';
        }
   
}

function hienthiYK(chon, ND_YK) {
    var nd = document.getElementById(ND_YK);
        if (chon==1) {
            try {
                nd.style.left =  event.clientX + 5;
                nd.style.top  =  event.clientY + document.documentElement.scrollTop + document.body.scrollTop - 20 ; //parseInt(event.clientY + 5) + parseInt(document.body.scrollTop);
            }
            catch(e){
                try {
                    nd.style.left = event.clientX + window.scrollX + 'px';
                    nd.style.top =  event.clientY + window.scrollY + 'px';

                }
                catch(ex){}
            }
            var i;
            nd.style.display = 'block';
            try { nd.style.opacity=1; } catch(ex1) {}
            try { nd.filters.alpha.opacity = 50; } catch(ex2) {}
        }
        else {
            nd.style.display = 'none';
        }  
}
//function hienthiYK(chon, ND_YK) {
//    var nd = document.getElementById(ND_YK);
//        if (chon==1) {
//            try {
//                nd.style.left =  event.clientX + 5; 
//                nd.style.top  =  event.clientY + document.documentElement.scrollTop + document.body.scrollTop - 20 ; //parseInt(event.clientY + 5) + parseInt(document.body.scrollTop);
//            }
//            catch(e){
//                try {
//                    nd.style.left = event.clientX + window.scrollX + 'px';
//                    nd.style.top =  event.clientY + window.scrollY + 'px';

//                }
//                catch(ex){}
//            }
//            var i
//            nd.style.display = 'block';
//            nd.style.opacity=1;
//            //nd.filters.alpha.opacity = 50;
//        }
//        else {
//            nd.style.display = 'none';
//        }   
//}


function roll_over(img_name, img_src)
   {
   document[img_name].src = img_src;
   }


/*
Doan ma tuyet roi
*/
/*
// Set the number of snowflakes (more than 30 - 40 not recommended)
var snowmax=35

// Set the colors for the snow. Add as many colors as you like
var snowcolor=new Array("#AAAACC","#DDDDFF","#CCCCDD","#F3F3F3","#F0FFFF")

// Thiết kế mặt chữ (font)
var snowtype=new Array("Arial Black","Arial Narrow","Times","Comic Sans MS")

// Thiết kế kiểu bông tuyết (ví dụ: * )
var snowletter="*"

// Thiết kế tốc độ rơi của tuyết (recommended values range from 0.3 to 2)
var sinkspeed=0.6

// Kích thước bông tuyết nè!
var snowmaxsize=22

// Kích thước lớn nhất của tuyết nè..
var snowminsize=8

// Thiết kế snowing-zone
// Set 1 for all-over-snowing, set 2 for left-side-snowing 
// Set 3 for center-snowing, set 4 for right-side-snowing
var snowingzone=1

  /*
   //   * NO CONFIGURATION BELOW HERE *


// Xin bạn đừng đụng đến phần dưới đây..
var snow=new Array()
var marginbottom
var marginright
var timer
var i_snow=0
var x_mv=new Array();
var crds=new Array();
var lftrght=new Array();
var browserinfos=navigator.userAgent 
var ie5=document.all&&document.getElementById&&!browserinfos.match(/Opera/)
var ns6=document.getElementById&&!document.all
var opera=browserinfos.match(/Opera/)  
var browserok=ie5||ns6||opera

function randommaker(range) {        
    rand=Math.floor(range*Math.random())
    return rand
}

function initsnow() {
    if (ie5 || opera) {
        marginbottom = document.body.clientHeight
        marginright = document.body.clientWidth
    }
    else if (ns6) {
        marginbottom = window.innerHeight
        marginright = window.innerWidth
    }
    var snowsizerange=snowmaxsize-snowminsize
    for (i=0;i<=snowmax;i++) {
        crds[i] = 0;                      
        lftrght[i] = Math.random()*15;         
        x_mv[i] = 0.03 + Math.random()/10;
        snow[i]=document.getElementById("s"+i)
        snow[i].style.fontFamily=snowtype[randommaker(snowtype.length)]
        snow[i].size=randommaker(snowsizerange)+snowminsize
        snow[i].style.fontSize=snow[i].size
        snow[i].style.color=snowcolor[randommaker(snowcolor.length)]
        snow[i].sink=sinkspeed*snow[i].size/5
        if (snowingzone==1) {snow[i].posx=randommaker(marginright-snow[i].size)}
        if (snowingzone==2) {snow[i].posx=randommaker(marginright/2-snow[i].size)}
        if (snowingzone==3) {snow[i].posx=randommaker(marginright/2-snow[i].size)+marginright/4}
        if (snowingzone==4) {snow[i].posx=randommaker(marginright/2-snow[i].size)+marginright/2}
        snow[i].posy=randommaker(2*marginbottom-marginbottom-2*snow[i].size)
        snow[i].style.left=snow[i].posx
        snow[i].style.top=snow[i].posy
    }
    movesnow()
}

function movesnow() {
    for (i=0;i<=snowmax;i++) {
        crds[i] += x_mv[i];
        snow[i].posy+=snow[i].sink
        snow[i].style.left=snow[i].posx+lftrght[i]*Math.sin(crds[i]);
        snow[i].style.top=snow[i].posy
        
        if (snow[i].posy>=marginbottom-2*snow[i].size || parseInt(snow[i].style.left)>(marginright-3*lftrght[i])){
            if (snowingzone==1) {snow[i].posx=randommaker(marginright-snow[i].size)}
            if (snowingzone==2) {snow[i].posx=randommaker(marginright/2-snow[i].size)}
            if (snowingzone==3) {snow[i].posx=randommaker(marginright/2-snow[i].size)+marginright/4}
            if (snowingzone==4) {snow[i].posx=randommaker(marginright/2-snow[i].size)+marginright/2}
            snow[i].posy=0
        }
    }
    var timer=setTimeout("movesnow()",50)
}

for (i=0;i<=snowmax;i++) {
    document.write("<span id='s"+i+"' style='position:absolute;top:-"+snowmaxsize+"'>"+snowletter+"</span>")
}
if (browserok) {
    window.onload=initsnow
}
*/
//Het doan ma tuyet roi