function checkedItems(item) {
	var maxDifferentials = 3;
	var checkedDifferentialCount = 0;
	for (checkBoxOffset = 0; checkBoxOffset < document.differential_diagnosis_form.DifferentialDiagnosis.length; checkBoxOffset++) {
		if (document.differential_diagnosis_form.DifferentialDiagnosis[checkBoxOffset].checked) {
			checkedDifferentialCount++;
		}
	}
	if (checkedDifferentialCount > maxDifferentials) {
		item.checked = false;
		alert("You may select up to " + maxDifferentials + " diagnoses to compare with {HY diagnosis name}.");
	}
}

function atLeastOne(diagnosisName) {
	var diffCounter = 0;
	var piis = new Array();
	var piisString = "";
	var j=0;
	for (i = 0; i < document.differential_diagnosis_form.DifferentialDiagnosis.length; i++) {
	    var ddx = document.differential_diagnosis_form.DifferentialDiagnosis[i];
		if (ddx.checked || ddx.type=='hidden') {
			diffCounter = diffCounter + 1;
			piis[j] = ddx.value;
			j++;
		}
	}
	for (j = 0; j < piis.length; j++) {
		if (j+1 == piis.length)
			piisString += piis[j];
		else 
			piisString += piis[j] + ", ";
	}
	document.getElementById("piis").value = piisString;
	if (diffCounter <= 1) {
		alert("You must check at least one diagnosis to compare with " + diagnosisName + ".");
		return false;
	}
	return true;
}