chi = 4 //current hidden index;

function showMore() {

if(chi>9) {exit();}

document.getElementById('post-'+chi+'_'+'a').style.display="";
document.getElementById('post-'+chi+'_'+'b').style.display="";

chi++;

}
function showLess() {

if(chi<2) {exit();}

chi--;

document.getElementById('post-'+chi+'_'+'a').style.display="none";
document.getElementById('post-'+chi+'_'+'b').style.display="none";
}