function swapSurveyChoice(obj){
	if(obj.checked){
		for(i=0;i<document.survey.elements.length;i++){
				if(document.survey.elements[i].name.indexOf("check_")!=-1){
						if(document.survey.elements[i].name!=obj.name){
								document.survey.elements[i].checked=false;
							}
					}
			}
	}
}