Count the number of elements with a specific class, then add an ID that numbers them

问题

I'm very new to this, just trying to piece together snippets from other posts.

I'm unsure how to count the number of elements on a page, then add a class to differentiate them with a number.

<script type="text/javascript">
$(document).ready(function(){
    $('.item').each(function (e) { $(this).addClass('count' + e); });
});
</script>

<div class="item"></div>
<div class="item"></div>
<div class="item"></div>

output to:

<div class="item count1"></div>
<div class="item count2"></div>
<div class="item count3"></div>

回答1:

Try this

$('div.item').each(function(i,n){ $(n).addClass('count' + (i + 1));});

回答2:

Try this:

$('.item').each(function (i, e) { $(e).addClass('count' + i); });

回答3:

$('.item').addClass(function(i){
    return "count" + (i + 1);
});

回答4:

What you have is just fine if you just change:

$(this).addClass('count' + e);

to

$(this).addClass('count' + (e + 1));

来源：https://stackoverflow.com/questions/11478777/count-the-number-of-elements-with-a-specific-class-then-add-an-id-that-numbers