function swapClass(arg){

 if((arg.substring(0,2) == "e_")|(arg.substring(0,2) == "r_")){
    for (var i = 0; el = document.getElementById('e_' + i); el){ 
      if("e_"+i != arg){
          el.style.display = "none";
      }else{
          el.style.display = "block";
      }
      i++; 
    }
    for (var i = 0; el = document.getElementById('r_' + i); el){ 
      if("r_"+i != arg){
          el.style.display = "none";
      }else{
          el.style.display = "block";
      }
      i++; 
    }
 }
 if(arg.substring(0,2) == "m_"){
    for (var i = 0; el = document.getElementById('m_' + i); el){ 
      if("m_"+i != arg){
          el.style.display = "none";
      }else{
          el.style.display = "block";
	      //if(i==0){
	      //   document.getElementById('e_' + i).style.display = "block";
   	      //}
      }
      i++; 
    }
 }
}