function kengen(){

D       = new Date();

yyyy = D.getFullYear();
mm   = D.getMonth() + 1;
dd   = D.getDate();

hh   = D.getHours();
ii   = D.getMinutes();
ss   = D.getSeconds();

mm = ("00" + mm ).substr( ("00" + mm ).length -2 , 2 );
dd = ("00" + dd ).substr( ("00" + dd ).length -2 , 2 );
hh = ("00" + hh ).substr( ("00" + hh ).length -2 , 2 );
ii = ("00" + ii ).substr( ("00" + ii ).length -2 , 2 );
ss = ("00" + ss ).substr( ("00" + ss ).length -2 , 2 );

document.getElementById('kengen').value = ''+yyyy+mm+dd+hh+ii+ss+'';
}