How to cycle through siblings using jQuery?
I have the folowing code:
html:
<div class="container">
<div class="selected">A</div>
<div>B</div>
<div>C</div>
<div>D</div>
</div>
<button id="next">next!</button>
jQuery:
$("#next").click(function() {
$(".selected").remove开发者_如何学GoClass("selected").next().addClass("selected");
});
What i want is loop through the divs in the container. I can do this to cycle:
$("#next").click(function() {
if ($(".selected").next().length == 0) {
$(".selected").removeClass("selected").siblings(":nth-child(1)").addClass("selected");
}
else {
$(".selected").removeClass("selected").next().addClass("selected");
}
});
But i think there is a simpler way. How can i make it simpler ? (I don't mind if you don't use the next()
function).
jsFiddle: http://jsfiddle.net/S28uC/
I 'd prefer siblings.first()
instead of siblings(":nth-child(1)")
, but in essence you won't be able to wrap around without using some variant of next().length
.
Update: If I were writing this from scratch, this is how I 'd do it:
$("#next").click(function() {
var $selected = $(".selected").removeClass("selected");
var divs = $selected.parent().children();
divs.eq((divs.index($selected) + 1) % divs.length).addClass("selected");
});
This approach is motivated by two factors:
- When you want to cycle over a collection indefinitely, modulo comes to mind
- Getting rid of the
if
makes for smarter-looking code
When setting the value of divs
I preferred $selected.parent().children()
over the equivalent $selected.siblings().add($selected)
as a matter of taste -- there are practically endless possibilities.
One simple way is this :
$("#container").find("div:eq(0)").addClass("selected");
how about this.
...
var selected = $(".selected").removeClass("selected");
if (jQuery(selected).next().addClass("selected").length == 0
{jQuery(selected).siblings().first().addClass("selected");};
...
In old good AI manner you try to do the deed (addClass), if it worked (length <> 0) nothing more to do, otherwise you try again on the first of the siblings.
You can try this
var cont = $('.container'),
i = 0;
$("#next").on('click', function() {
cont.children().removeClass('selected');
i += 1;
if ( i === document.querySelectorAll('.container div').length ) { i = 0; }
cont.children().eq(i).addClass('selected');
});
var cont = $('.container'),
i = 0;
$("#next").on('click', function() {
cont.children().removeClass('selected');
// increase index for each click
i += 1;
// reset i if it reached to last index
//(hack to force next to go back to first element when we are at the end)
if ( i === document.querySelectorAll('.container div').length ) {
i = 0;
}
cont.children().eq(i).addClass('selected');
});
.selected {
background-color: yellow;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="container">
<div class="selected">A</div>
<div>B</div>
<div>C</div>
<div>D</div>
</div>
<button id="next">next!</button>
simply you will increase i
for each click and when it reach the end (div
s length ) it will be reset.
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