function change_big_pic_bg(tag_id){
 var bg_types=[
  '/_img/big_pic_top_a.jpg',
  '/_img/big_pic_top_c.jpg',
  '/_img/big_pic_top_b.jpg'
 ];
 if(bg_types.length<1)return;
 var b=document.getElementById(tag_id);
 b.style.backgroundImage='url("'+bg_types[Math.floor(Math.random()*bg_types.length)]+'")';
}

function change_bn_pic(arr_name,tag_id){
 var d=document;
 var c_type=arr_name;
 if(c_type.length<1)return;
 var rnd=c_type[Math.floor(Math.random()*c_type.length)];
 var c_block=d.getElementById(tag_id);
 var gen_link=d.createElement('a');
 gen_link.setAttribute('href',rnd['link']);
 if (rnd['target'] != undefined) {
 	gen_link.setAttribute('target',rnd['target']);
 }
 if(rnd['a_class']){
  gen_link.className=rnd['a_class'];
 }
 var gen_img=d.createElement('img');
 if(rnd['img_class']){
  gen_img.className=rnd['img_class'];
 }
 gen_img.setAttribute('src',rnd['img_src']);
 gen_link.appendChild(gen_img);
 c_block.appendChild(gen_link);
}