function  seczfld(n)
{
for(i=0;i<secTable1.cells.length;i++)
secTable1.cells[i].className="zfld2";
secTable1.cells[n].className="zfld1";
for(i=0;i<mainTable1.tBodies.length;i++)
mainTable1.tBodies[i].style.display="none";
mainTable1.tBodies[n].style.display="block";
}