function over1(CaoPhong) {

  CaoPhong.style.backgroundImage='url(images/blue_100x30.jpg)';

}

function out1(CaoPhong) {

  CaoPhong.style.backgroundImage='url(images/white.gif)';

}

function over2(CaoPhong) {

  CaoPhong.style.backgroundImage='url(images/blue_60x30.jpg)';

}

function out2(CaoPhong) {

  CaoPhong.style.backgroundImage='url(images/white.gif)';

}

function over3(CaoPhong) {

  CaoPhong.style.backgroundImage='url(images/blue_80x30.jpg)';

}

function out3(CaoPhong) {

  CaoPhong.style.backgroundImage='url(images/white.gif)';

}



img=new Array()         
img[0]=new Image()
img[1]=new Image()
img[2]=new Image()
img[3]=new Image()

img[0].src="images/prod_tehn.jpg"    
img[1].src="images/prod_tehn2.jpg"    
img[2].src="images/service.jpg"
img[3].src="images/service2.jpg"

function ChgImg(NumImg,Action)
{

i=eval(NumImg);

if(Action)
{
document.images[i].src=img[i*2+1].src
}
else      
document.images[i].src=img[i*2].src
}