I have four paragraphs inside a div and the first child (or rather the first paragraph) is visible. Besides, I have two buttons ("next" and "previous") and when the button is clicked I have to hide the current paragraph and show the next/previous paragraph.
I've tried to write a function that accomplishes this goal but it's doesn't seem to be working. It doesn't hide the current paragraph and doesn't show the next/previous sibling.
Here is an example:
var show = function(elem) {
elem.style.display = 'block';
};
var hide = function(elem) {
elem.style.display = 'none';
}
var toggle = function(elem, next) {
if (window.getComputedStyle(elem).display === 'block') {
hide(elem);
show(next);
return;
}
};
var count = 0;
document.addEventListener('click', function(event) {
if (!event.target.classList.contains('toggle')) return;
event.preventDefault();
var e = document.getElementById("bal");
var content = e.childNodes[count];
count++;
var next = content.nextSibling;
if (!content) return;
toggle(content, next);
}, false);#bal {
width: 48%;
border: 1px solid red;
padding: 1em;
}
#bal p {
display: none;
}
#bal p:nth-child(1) {
display: block;
}
#jobb {
width: 48%;
float: right;
}<div id="jobb">
<form id="gombok">
<span>
<input type="button" name="previous" value="Previous">
<input type="button" class="toggle" href="#bal" name="next" value="Next">
</span>
</form>
</div>
<div id="bal" class="sib">
<p>Paragraph 1</p>
<p>Paragraph 2</p>
<p>Paragraph 3</p>
<p>Paragraph 4</p>
</div>This function doesn't recognize the current paragraph and if I click two times on the "next" button it deletes the text of the first paragraph.
@dbramwell has a valuable explanation why your code wasn't working:
- Using childNodes rather than children. As you're trying to set style on them, you need to use children to get elements rather than nodes. See here.
if(!content) return;, you need to check if "next" exists, rather than content, as on the last paragraph content will exist when next doesn't
and also corrected your function:
var show = function (elem){
elem.style.display = 'block';
};
var hide = function (elem){
elem.style.display = 'none';
}
var toggle = function(elem, next){
if (window.getComputedStyle(elem).display === 'block'){
hide(elem);
show(next);
return;
}
};
var count = 0;
document.addEventListener('click', function(event){
if (!event.target.classList.contains('toggle')) return;
event.preventDefault();
var e = document.getElementById("bal");
var content = e.children[count];
count++;
var next = e.children[count];
if(!next) return;
toggle(content, next);
}, false);<!DOCTYPE html>
<html lang="hu">
<head>
<title>JS példák</title>
<meta charset="utf-8">
<meta name="description" content="JavaScript példák">
<script src="utils.js"></script>
<script src="./view_para.js"></script>
<style type="text/css">
#bal {
width: 48%;
border: 1px solid red;
padding: 1em;
}
#bal p {
display: none;
}
#bal p:nth-child(1) {
display: block;
}
#jobb {
width: 48%;
float: right;
}
</style>
</head>
<body>
<div id="jobb">
<form id="gombok">
<span>
<input type="button" name="previous" value="Előző">
<input type="button" class="toggle" href="#bal" name="next" value="Következő">
</span>
</form>
</div>
<div id="bal" class="sib">
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam
semper felis in nunc tincidunt lacinia. Aenean interdum,
lorem pretium maximus euismod, dolor tellus porta velit, sed
dapibus ex velit non ante. Morbi consequat rhoncus
erat, a laoreet felis commodo eget. Phasellus sed justo nibh.
Quisque ut felis malesuada, dictum erat vel, vehicula
nunc. Sed quis facilisis enim. Sed non magna nisl. Duis
pellentesque tempus mollis.</p>
<p>In ultrices mauris risus, ac blandit arcu vehicula vel. Mauris in
nulla nulla. Praesent dignissim justo at lorem
tempus molestie. Nunc interdum, justo non iaculis mollis, quam
ipsum mollis massa, id dignissim odio purus quis
ex. Ut a odio venenatis, malesuada diam et, blandit magna. Nam
scelerisque purus ut risus interdum, et vehicula
augue vestibulum. Proin mattis vehicula arcu, sit amet suscipit
velit malesuada sed. In hac habitasse platea
dictumst. Ut non laoreet dolor. Nunc pellentesque nulla at justo
maximus dignissim. </p>
<p>ellentesque convallis sapien eget tortor fermentum, nec consequat
lacus interdum. Sed id pulvinar risus, eu ornare
tellus. Morbi non ex magna. Nunc sed massa id dolor ultrices
consequat. Curabitur fermentum nibh quis sollicitudin
condimentum. Integer a quam vitae quam fringilla consectetur.
Donec vehicula, risus sed sagittis condimentum,
risus neque luctus mauris, accumsan consectetur lectus nisi id
tellus. Quisque eu sapien non lectus imperdiet
tincidunt consequat non metus. Nulla egestas iaculis arcu sed
elementum. Praesent pellentesque sem purus. Nulla
hendrerit leo lacus, sit amet sodales ante porttitor at. Fusce
dapibus laoreet dui, sit amet ornare odio mollis
non. In hac habitasse platea dictumst. Praesent non ex at nunc
ullamcorper interdum. </p>
<p>Duis tortor leo, ultricies quis placerat vel, scelerisque eu
augue. Duis est odio, interdum sit amet ullamcorper
eget, tincidunt et lectus. Aliquam erat volutpat. Donec tempus
porttitor consectetur. Pellentesque ac enim vestibulum,
eleifend arcu et, hendrerit ligula. Sed quis magna metus.
Quisque dignissim metus eget iaculis commodo.</p>
<p>Interdum et malesuada fames ac ante ipsum primis in faucibus.
Vestibulum et est gravida, mattis arcu sed, ultricies
elit. Sed vitae nisi ac lacus tincidunt varius et eu augue.
Etiam ultrices nunc vitae lacinia sagittis. Curabitur
molestie ac tellus non porttitor. Suspendisse potenti. Praesent
facilisis semper iaculis. Sed justo enim, imperdiet
vitae aliquet id, tempor ut orci. Nunc sed risus arcu. In
imperdiet dui eget erat elementum egestas. Pellentesque
eget urna vitae nulla dapibus euismod. Curabitur nisl diam,
pretium id mi posuere, molestie gravida justo. </p>
</div>However, this is not the way you should design your code for an easy task like this. I wrote a much simpler function that should do the task equally good.
var count = 0;
function bla() {
var num = document.querySelectorAll("div#bal p").length - 1;
if(count < 0) {
count = num;
} else if (count > num) {
count = 0;
}
var all = document.querySelectorAll("div p");
for (var i = 0; i < all.length; i++) {
all[i].style.display = "none";
}
document.querySelectorAll("div p")[count].style.display = "block";
}div > p {
display: none;
}
div > p:first-child {
display: block;
}<div>
<p>P1</p>
<p>P2</p>
<p>P3</p>
<p>P4</p>
</div>
<button onclick="bla(count++);">Next</button>
<button onclick="bla(count--);">Previous</button>Even with your (not shortened) example this is easy to accomplish.
var count = 0;
function bla() {
var num = document.querySelectorAll("div#bal p").length - 1;
if (count < 0) {
count = num;
} else if (count > num) {
count = 0;
}
var all = document.querySelectorAll("div#bal p");
for (var i = 0; i < all.length; i++) {
all[i].style.display = "none";
}
document.querySelectorAll("div#bal p")[count].style.display = "block";
}#bal {
width: 48%;
border: 1px solid red;
padding: 1em;
}
#bal p {
display: none;
}
#bal p:nth-child(1) {
display: block;
}
#jobb {
width: 48%;
float: right;
}<div id="jobb">
<form id="gombok">
<span>
<input type="button" onclick="bla(count--)" name="previous" value="Előző">
<input type="button" onclick="bla(count++)" class="toggle" href="#bal" name="next" value="Következő">
</span>
</form>
</div>
<div id="bal" class="sib">
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam semper felis in nunc tincidunt lacinia. Aenean interdum, lorem pretium maximus euismod, dolor tellus porta velit, sed dapibus ex velit non ante. Morbi consequat rhoncus erat, a laoreet felis
commodo eget. Phasellus sed justo nibh. Quisque ut felis malesuada, dictum erat vel, vehicula nunc. Sed quis facilisis enim. Sed non magna nisl. Duis pellentesque tempus mollis.</p>
<p>In ultrices mauris risus, ac blandit arcu vehicula vel. Mauris in nulla nulla. Praesent dignissim justo at lorem tempus molestie. Nunc interdum, justo non iaculis mollis, quam ipsum mollis massa, id dignissim odio purus quis ex. Ut a odio venenatis,
malesuada diam et, blandit magna. Nam scelerisque purus ut risus interdum, et vehicula augue vestibulum. Proin mattis vehicula arcu, sit amet suscipit velit malesuada sed. In hac habitasse platea dictumst. Ut non laoreet dolor. Nunc pellentesque nulla
at justo maximus dignissim. </p>
<p>ellentesque convallis sapien eget tortor fermentum, nec consequat lacus interdum. Sed id pulvinar risus, eu ornare tellus. Morbi non ex magna. Nunc sed massa id dolor ultrices consequat. Curabitur fermentum nibh quis sollicitudin condimentum. Integer
a quam vitae quam fringilla consectetur. Donec vehicula, risus sed sagittis condimentum, risus neque luctus mauris, accumsan consectetur lectus nisi id tellus. Quisque eu sapien non lectus imperdiet tincidunt consequat non metus. Nulla egestas iaculis
arcu sed elementum. Praesent pellentesque sem purus. Nulla hendrerit leo lacus, sit amet sodales ante porttitor at. Fusce dapibus laoreet dui, sit amet ornare odio mollis non. In hac habitasse platea dictumst. Praesent non ex at nunc ullamcorper interdum.
</p>
<p>Duis tortor leo, ultricies quis placerat vel, scelerisque eu augue. Duis est odio, interdum sit amet ullamcorper eget, tincidunt et lectus. Aliquam erat volutpat. Donec tempus porttitor consectetur. Pellentesque ac enim vestibulum, eleifend arcu et,
hendrerit ligula. Sed quis magna metus. Quisque dignissim metus eget iaculis commodo.</p>
<p>Interdum et malesuada fames ac ante ipsum primis in faucibus. Vestibulum et est gravida, mattis arcu sed, ultricies elit. Sed vitae nisi ac lacus tincidunt varius et eu augue. Etiam ultrices nunc vitae lacinia sagittis. Curabitur molestie ac tellus
non porttitor. Suspendisse potenti. Praesent facilisis semper iaculis. Sed justo enim, imperdiet vitae aliquet id, tempor ut orci. Nunc sed risus arcu. In imperdiet dui eget erat elementum egestas. Pellentesque eget urna vitae nulla dapibus euismod.
Curabitur nisl diam, pretium id mi posuere, molestie gravida justo. </p>
</div>Collected from the Internet
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