function changeImage1(){
    document.myimg.src="image/category_show.jpg";
}
function changeImage2(){
    document.myimg.src="image/category_show2.jpg";
}
function changeImage3(){
    document.myedit.src="image/category_edit.jpg";
}
function changeImage4(){
    document.myedit.src="image/category_edit2.jpg";
}
function changeImage5(){
    document.mydvd.src="image/category_dvd.jpg";
}
function changeImage6(){
    document.mydvd.src="image/category_dvd2.jpg";
}
function changeImage7(){
    document.p2g.src="image/category_dvdwrite.jpg";
}
function changeImage8(){
    document.p2g.src="image/category_dvdwrite2.jpg";
}