layui中多选框 默认全选

多选框默认全选的代码是：

layui.use(['form'], function(){
  var form = layui.form;
  
  //全选
  form.on('checkbox(selectAll)', function(data){
    var child = $(data.elem).parents('table').find('tbody input[type="checkbox"]');
    child.each(function(index, item){
      item.checked = data.elem.checked;
    });
    form.render('checkbox');
  });

  //子选项
  form.on('checkbox(selectOne)', function(data){
    var child = $(data.elem).parents('table').find('tbody input[type="checkbox"]');
    var flag = true;
    child.each(function(index, item){
      if(!item.checked){
        flag = false;
      }
    });
    if(flag){
      $(data.elem).parents('table').find('thead input[type="checkbox"]').get(0).checked = true;
    }else{
      $(data.elem).parents('table').find('thead input[type="checkbox"]').get(0).checked = false;
    }
    form.render('checkbox');
  });
});

希望能够帮到你！