let n2=10
let s2
document.write("<table>");
for (i=1; i<=n2; i=i+1){
document.write("<tr>")
for (j=1;j<=n2;j=j+1) {
st=(i/j)
if (st == 0) s2="class='r3'";
else s2="class='r4'";
document.write("<td "+s2+"></td>");
}
document.write("</tr>")
}
document.write("</table>")
if (st == 0) s2="class='r3'";
на if (st == 1) s2="class='r3'";
if (st <= 1 ) s2="class='r3'";