function count_select_num(obj)
{
	var number=0;
	var x=obj;
    for(var i=0;i<x.length;i++)
    {
       if(x[i].checked) 
       {
          number++;
       }
	} 
	return number;
}

function selectall_click(){
		  var inputs = document.getElementsByTagName('input');
          var inputsLen = inputs.length;
          var sign=1;
		  for (var i = 0; i < inputsLen ; i++ ){
                if (inputs[i].type.toLowerCase() == 'checkbox'){
                    if(inputs[i].checked == false){
					     sign=2;
					}
					
                 }
          }
		  if(sign==2){
		         for (var i = 0; i < inputsLen ; i++ ){
		              if (inputs[i].type.toLowerCase() == 'checkbox'){
                         inputs[i].checked = true;
					  }
		         }
		  }else{
		         for (var i = 0; i < inputsLen ; i++ ){
		               if (inputs[i].type.toLowerCase() == 'checkbox'){
                         inputs[i].checked = false;
					    }
		         }
		  }
}