每3个 div 包装一个 div

You can do it with .slice(), like this:

var divs = $("div > div");
for(var i = 0; i < divs.length; i+=3) {
divs.slice(i, i+3).wrapAll("<div class='new'></div>");
}

You can try out a demo here, all we're doing here is getting the elements you want to wrap and looping through them, doing a .wrapAll() in batches of 3 then moving to the next 3, etc. It will wrap 3 at a time and however many are left at the end, e.g. 3, 3, 3, 2 if that's the case.

The Plugin

$(function() {
$.fn.EveryWhat = function(arg1) {
var arr = [];
if($.isNumeric(arg1)) {
$.each(this, function(idx, item) {
var newNum = idx + 1;
if(newNum%arg1 == 0)
arr.push(item);
});
}
return this.pushStack(arr, "EveryWhat", "");
}
});

How to use it.

Call EveryWhat() on the element and put in a number for every element you would like to collect.

$("div").EveryWhat(2).wrapInner('<div class="new" />');

wrapinner's quotes should have a properly formatted <div class="new" /> with a class and closing tag. Stackoverflow prevents me from showing what that looks like but here is a link of a self closing div.

What it should look like

That will wrap every other number that you specified. I'm using jquery 1.8.2. so remember use selector call EveryWhat(3) and a number for every time. Of course putting it at the bottom of the page or wrapping it in a

$(document).ready(function() {
//place above code here
});

You could use every nth and then .wrapInner('<div class="new" />') for the same results.

Here is a more usable version of Nick's above:

window.WrapMatch = function(sel, count, className){
for(var i = 0; i < sel.length; i+=count) {
sel.slice(i, i+count).wrapAll('<div class="'+className+'" />');
}
}

You would use this like:

var ele = $('#menu > ul > li');
window.WrapMatch(ele, 5, 'new-class-name');

window should be replaced with your Handlers namespace, of course.

Updated: A slightly better version that leverages jQuery

(function($){
$.fn.wrapMatch = function(count, className) {
var length = this.length;
for(var i = 0; i < length ; i+=count) {
this.slice(i, i+count).wrapAll('<div '+((typeof className == 'string')?'class="'+className+'"':'')+'/>');
}
return this;
};
})(jQuery);

Use like:

$('.list-parent li').wrapMatch(5,'newclass');

The second parameter for the wrapper name is optional.

$(function() {
$.fn.WrapThis = function(arg1, arg2) { /*=Takes 2 arguments, arg1 is how many elements to wrap together, arg2 is the element to wrap*/


var wrapClass = "column"; //=Set class name for wrapping element


var itemLength = $(this).find(arg2).length; //=Get the total length of elements
var remainder = itemLength%arg1; //=Calculate the remainder for the last array
var lastArray = itemLength - remainder; //=Calculate where the last array should begin


var arr = [];


if($.isNumeric(arg1))
{
$(this).find(arg2).each(function(idx, item) {
var newNum = idx + 1;


if(newNum%arg1 !== 0 && newNum <= lastArray){
arr.push(item);
}
else if(newNum%arg1 == 0 && newNum <= lastArray) {
arr.push(item);
var column = $(this).pushStack(arr);
column.wrapAll('<div class="' + wrapClass + '"/>'); //=If the array reaches arg1 setting then wrap the array in a column
arr = [];
}
else if(newNum > lastArray && newNum !== itemLength){ //=If newNum is greater than the lastArray setting then start new array of elements
arr.push(item);
}
else { //=If newNum is greater than the length of all the elements then wrap the remainder of elements in a column
arr.push(item);
var column = $(this).pushStack(arr);
column.wrapAll('<div class="' + wrapClass + '"/>');
arr = []
}
});
}
}
});

I took Kyle's plugin idea and extended it to wrap automatically and take two arguments. It didn't work for me to begin with, but I got it running with a few edits and additions to the code.

To invoke the function just use the parent element of what you want to wrap and then set your arguments as follows.

$('#container').WrapThis(5, 'li');

The first argument is how many elements you want to wrap together and the second argument is the element type you would like to wrap.

You can change the class of the wrapping element in the main function under the variable wrapClass.

I have prepared this answer for another question that was duplicate of this one. So maybe my variant will be usefull for some one:

I think the solution to wrap all three elements is:

var $lines = $('.w-col'), // All Dom elelements with class .w-col
holder = []; //Collect DOM elelements


$lines.each(function (i, item) {
holder.push(item);


if (holder.length === 3) {
$(holder).wrapAll('<div class="w-row" />');
holder.length  = 0;
}
});


$(holder).wrapAll('<div class="w-row" />'); //Wrap last elements with div(class=w-row)

I have wrote the same code at jsbin with some improvements http://jsbin.com/necozu/17/ or http://jsbin.com/necozu/16/

I've written a generic chunk function that makes this quite easy to do:

$.fn.chunk = function(size) {
var arr = [];
for (var i = 0; i < this.length; i += size) {
arr.push(this.slice(i, i + size));
}
return this.pushStack(arr, "chunk", size);
}


$("div > div").chunk(3).wrap('<div class="new"></div>');

$.fn.chunk = function(size) {
var arr = [];
for (var i = 0; i < this.length; i += size) {
arr.push(this.slice(i, i + size));
}
return this.pushStack(arr, "chunk", size);
}


$("div > div").chunk(3).wrap('<div class="new"></div>');

div > div {
width: 50px;
height: 50px;
background: blue;
margin: 2px;
float: left;
}


div.new {
background: red;
height: auto;
width: auto;
overflow: auto;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
</div>