var m2=0;

function hesapla(form)
{
m2=Math.round(eval(form.metrekare.value));
if (m2>0)  {

 alcipanfx= Math.round(eval(m2 * 2));
 form.alcipanfx.value=alcipanfx+" m2"

 duvarc=Math.round(eval(m2*2.3/3))
 form.duvarc.value=duvarc+" boy"

 duvaru=Math.round(eval(m2*0.9/3))
 form.duvaru.value=duvaru+" boy"

 dubelvida=Math.round(eval(m2*2))
 form.dubelvida.value=dubelvida+" adet"


 borazanvida=Math.round(eval(m2*25))
 form.borazanvida.value=borazanvida+" adet"


 derzbandi=Math.round(eval(m2*3.4/90))
 form.derzbandi.value=derzbandi+" rulo"

 fugagips=Math.round(eval(m2*0.6/30))
 form.fugagips.value=fugagips+" torba"

 } else { alert("HATA: m² \"0\" dan büyük olmalıdır!");
 document.forms[0].metrekare.focus();}

 }