与子元素映射时，如何检查元素是父对象的第一个孩子？

Question

I am mapping all textarea in specific container. I need to check every textarea is first element of parent( $('.services') ). If not, then add a class to it.

There are several .services classes in page and added later after page loaded. Need to only show first textarea child for every .services classes. Each .services class have many textarea.

$('textarea').map(function (i) {
      /* if not first textarea of parent element $('.services') */
      $(this).addClass('hide');
});

How to do this?

Answer 1

$('.services > textarea').filter(function() {
    return $(this).index() !== 0;
}).addClass('hide');

Answer 2

Try with .each() like

$('.services textarea').each(function(){
    var indx = $(this).index(); 
    if(indx != 0) {
        $(this).addClass('hide');
    }
}); 

See this FIDDLE

Answer 3

$(".services").find("textarea:eq(0)");

参考查找和eq选择器

Answer 4

Why not hide all .services and then just show the first child?

$('.services').hide();
$('.services:first-child').show();

Answer 5

This should do it,

$('.services').each(function(){
   $(this).children('textarea').addClass('hide');
   $(this).children('textarea:first').removeClass('hide').show();
})

Answer 6

try this

$('.services').each(function(){
  if($(this).not(':first-child')){
    $(this).addClass('hide');
  }
}

or:

$('.services textarea:not(:first-child)').addClass('hide');

or:

$('.services').children().not(':first').addClass('hide');

Answer 7

Try this:

$('.services textarea').each(function(){
    var textarea = $(this);
    if(!textarea.is(':first')) {
        $(this).addClass('hide');
    }
});