Get next / previous element using JavaScript?
How do I get the next element in HTML using JavaScript?
Suppose I have three <div>
s and I get a reference to one in JavaScript code, I want to get which is the next <div>
and which is the previous.
use the nextSibling
and previousSibling
properties:
<div id="foo1"></div>
<div id="foo2"></div>
<div id="foo3"></div>
document.getElementById('foo2').nextSibling; // #foo3
document.getElementById('foo2').previousSibling; // #foo1
However in some browsers (I forget which) you also need to check for whitespace and comment nodes:
var div = document.getElementById('foo2');
var nextSibling = div.nextSibling;
while(nextSibling && nextSibling.nodeType != 1) {
nextSibling = nextSibling.nextSibling
}
Libraries like jQuery handle all these cross-browser checks for you out of the box.
Well in pure javascript my thinking is that you would first have to collate them inside a collection.
var divs = document.getElementsByTagName("div");
//divs now contain each and every div element on the page
var selectionDiv = document.getElementById("MySecondDiv");
So basically with selectionDiv iterate through the collection to find its index, and then obviously -1 = previous +1 = next within bounds
for(var i = 0; i < divs.length;i++)
{
if(divs[i] == selectionDiv)
{
var previous = divs[i - 1];
var next = divs[i + 1];
}
}
Please be aware though as I say that extra logic would be required to check that you are within the bounds i.e. you are not at the end or start of the collection.
This also will mean that say you have a div which has a child div nested. The next div would not be a sibling but a child, So if you only want siblings on the same level as the target div then definately use nextSibling checking the tagName property.
Really depends on the overall structure of your document.
If you have:
<div></div>
<div></div>
<div></div>
it may be as simple as traversing through using
mydiv.nextSibling;
mydiv.previousSibling;
However, if the 'next' div could be anywhere in the document you'll need a more complex solution. You could try something using
document.getElementsByTagName("div");
and running through these to get where you want somehow.
If you are doing lots of complex DOM traversing such as this I would recommend looking into a library such as jQuery.
There is a attribute on every HTMLElement, "previousElementSibling".
Ex:
<div id="a">A</div>
<div id="b">B</div>
<div id="c">c</div>
<div id="result">Resultado: </div>
var b = document.getElementById("c").previousElementSibling;
document.getElementById("result").innerHTML += b.innerHTML;
Live: http://jsfiddle.net/QukKM/
This will be easy... its an pure javascript code
<script>
alert(document.getElementById("someElement").previousElementSibling.innerHTML);
</script>