window.onload=function(){
	document.getElementById('estimateLo').disabled = true;
	document.getElementById('estimateHi').disabled = true;
	chkEstmOn();
}

function chkEstmOn(){
	if(document.getElementById('category_1').checked == true || document.getElementById('category_9').checked == true || document.getElementById('category_2').checked == true){
		if(document.getElementById('people_40').checked == true || document.getElementById('people_60').checked == true || document.getElementById('people_80').checked == true){
			document.getElementById('estimateLo').disabled = false;
			document.getElementById('estimateHi').disabled = false;
		} else {
			document.getElementById('estimateLo').disabled = true;
			document.getElementById('estimateHi').disabled = true;
		}
	} else {
		document.getElementById('estimateLo').disabled = true;
		document.getElementById('estimateHi').disabled = true;
	}
}