function cambia_img(){
var cur=Math.round(17*Math.random())
if (cur<=1)
document.getElementById('TABsfondo').className='sfondohome1' ;
else if (cur<=2)
document.getElementById('TABsfondo').className='sfondohome2' ;
else if (cur<=3)
document.getElementById('TABsfondo').className='sfondohome3';
else if (cur<=4)
document.getElementById('TABsfondo').className='sfondohome4';
else if (cur<=5)
document.getElementById('TABsfondo').className='sfondohome5';
else if (cur<=6)
document.getElementById('TABsfondo').className='sfondohome6';
else if (cur<=7)
document.getElementById('TABsfondo').className='sfondohome7';
else if (cur<=8)
document.getElementById('TABsfondo').className='sfondohome8';
else if (cur<=9)
document.getElementById('TABsfondo').className='sfondohome9';
else if (cur<=10)
document.getElementById('TABsfondo').className='sfondohome10';
else if (cur<=11)
document.getElementById('TABsfondo').className='sfondohome11';
else if (cur<=12)
document.getElementById('TABsfondo').className='sfondohome12' ;
else if (cur<=13)
document.getElementById('TABsfondo').className='sfondohome13';
else if (cur<=14)
document.getElementById('TABsfondo').className='sfondohome14';
else if (cur<=15)
document.getElementById('TABsfondo').className='sfondohome15';
else if (cur<=16)
document.getElementById('TABsfondo').className='sfondohome16';
else if (cur<=17) 
document.getElementById('TABsfondo').className='sfondohome17';
//else if (cur<=18)
//document.getElementById('TABsfondo').className='sfondohome18';
//else if (cur<=19)
//document.getElementById('TABsfondo').className='sfondohome19';
//else if (cur<=20)
//document.getElementById('TABsfondo').className='sfondohome20';
//else if (cur<=21)
//document.getElementById('TABsfondo').className='sfondohome21';
//else if (cur<=22)
//document.getElementById('TABsfondo').className='sfondohome22';
//else if (cur<=23)
//document.getElementById('TABsfondo').className='sfondohome23';
//else if (cur<=24)
//document.getElementById('TABsfondo').className='sfondohome24';
//else if (cur<=25)
//document.getElementById('TABsfondo').className='sfondohome25';
//else if (cur<=26)
//document.getElementById('TABsfondo').className='sfondohome26';
//else if (cur<=27)
//document.getElementById('TABsfondo').className='sfondohome27';
//else if (cur<=28)
//document.getElementById('TABsfondo').className='sfondohome28';
//else if (cur<=29)
//document.getElementById('TABsfondo').className='sfondohome29';
//else if (cur<=30)
//document.getElementById('TABsfondo').className='sfondohome30';
timer10();
}
function timer()
{ setTimeout("cambia_img();", 10);}
function timer10()
{ setTimeout("cambia_img();", 10000);}