function prev(){
 var scode = document.all.scode.value;
 if (scode=="1")
 {
 return false;
 }else if (scode=="2")
 {
 document.all.scode.value=1
 document.all.line1.style.display="block"
 document.all.line2.style.display="none"
 document.all.line3.style.display="none"
 }else if (scode=="3")
 {
 document.all.scode.value=2
 document.all.line1.style.display="none"
 document.all.line2.style.display="block"
 document.all.line3.style.display="none"
 }
 
}
function next(){
 var scode = document.all.scode.value;
 if (scode=="1")
 {
 document.all.scode.value=2
 document.all.line1.style.display="none"
 document.all.line2.style.display="block"
 document.all.line3.style.display="none"
 }else if (scode=="2")
 {
 document.all.scode.value=3
 document.all.line1.style.display="none"
 document.all.line2.style.display="none"
 document.all.line3.style.display="block"
 }else if (scode=="3")
 {
 return false;
 }
 
}