复选框未在javascript中检查？

function handleCheckboxClick(event){

    if(document.getElementById(event.target.id).checked){

      document.getElementById(event.target.id.concat("_visible")).setAttribute("checked", "true");
      console.log(document.getElementById(event.target.id.concat("_visible")));		   				   		
  }
}

var requiredCheckboxes = document.getElementsByClassName("checkbox_required");

for (var i = 0, max = requiredCheckboxes.length; i < max; i++){
   requiredCheckboxes[i].addEventListener('click', handleCheckboxClick);		    
}

    			
	

		

			Property
		
		

			Visible
		
		

			Required
		
	
	
	

		

			Email