<input type="checkbox" name="test[]" value="test1" onclick="choise_chk(this)"> test1
<input type="checkbox" name="test[]" value="test2" onclick="choise_chk(this)"> test2
<input type="checkbox" name="test[]" value="test3" onclick="choise_chk(this)"> test3
<SCRIPT LANGUAGE="JavaScript">
function choise_chk(chk) {
var target = document.getElementsByName('test[]');
var num = 0;
var ropNum = 2; // 개수 임의지정
for(var i=0; i < target.length; i++) {
if(target[i].checked == true) {
num++;
}
}
if(num > ropNum) {
chk.checked = false;
return alert(ropNum + "개 이상 체크 불가능합니다." );
}
}
</SCRIPT>