JQuery append not working in IE 7

JQuery append not working in IE 7

Here is my code to insert table rows dynamically. It's not working with
ie7. But working with ie8,ie9 ,Chrome, Firefox.
for(var lvl=0;lvl<13;lvl++)
{
$("#check-form tbody").append( "<tr />");
for(var fchr=6;fchr<=36;fchr+=3)
{
if(fchr==6)
$("#check-form tbody").append( "<th scope=\"row\">"+hpa[lvl]+"
MB</th>");
$("#check-form tbody").append("<td><input type=\"checkbox\"
value="+('0'+fchr).slice(-2)+"_"+hpa[lvl]+"
id="+('0'+fchr).slice(-2)+"_"+hpa[lvl]+"
class=\"chkChart\"></input></td>");
}
}
Please help