function selectall_check(){
		var checks = document.getElementById('frm_gerusuario').getElementsByTagName('input');

		if(document.getElementById('select_all').checked == true){
			for(i = 0; i < checks.length; i++){
				if(checks[i].type == 'checkbox'){

					if(checks[i].id != 'select_all'){
						checks[i].checked=true;
					}
				}
			}
		} else {
			for(i = 0; i < checks.length; i++){
				if(checks[i].type == 'checkbox'){

					if(checks[i].id != 'select_all'){
						checks[i].checked=false;
					}
				}
			}
		}

	}