i=0;
function hyouji(){
document.getElementById("slide").src=preimg[i];
document.getElementById("slide").style.margin="0px auto";
document.getElementById("text").innerHTML="Showing <b>"+(i+1)+"</b> of <b>"+n+"</b>";
document.getElementById("text2").innerHTML="Showing <b>"+(i+1)+"</b> of <b>"+n+"</b>";
}
function pre(){
 if(i>0){
 i=0;
 hyouji();
 }
 }
function mae(){if(i>0){i--;hyouji();}else{i=n-1;hyouji();}}
function tugi(){if(i<n-1){i++;hyouji();}else{i=0;hyouji();}}
function back1(){
 if(i>=0){
 i=30;
 hyouji();
 }
 }