How to reduce javascript code that use JQuery and .each() - javascript

I have tried to reduce following code
var wgDialog
= jQuery(".ui-dialog.ui-overlay-visible",window.parent.document)
.each
(function(nIndex)
{
var sWidgetName = $(this).attr('data-widgetvar');
var wgDialog = window.parent.PF(sWidgetName);
});
to this code
var jqDialog
= jQuery(".ui-dialog.ui-overlay-visible",window.parent.document)
.children(":first-child");
var sWidgetName = jqDialog.attr('data-widgetvar');
var wgDialog = window.parent.PF(sWidgetName);
but this doesn't work !
The sWidgetName variable is always undefined in last code.
What is my mistake ?

With help of comments, I have found a solution.
I must use get(0) to obtain first element in list returner by JQuery().
And I must use $(jqDialog) instead of jqDialog to get 'data-widgetvar' attribute.
Here is my new code
var jqDialog
= jQuery(".ui-dialog.ui-overlay-visible",window.parent.document)
.get(0);
var sWidgetName = $(jqDialog).attr('data-widgetvar');
var wgDialog = window.parent.PF(sWidgetName);

Assuming you want to access an element with attribute data-widgetvar nested in an element having css classes ui-dialog and ui-overlay-visible you could do the following with plain javascript:
var myElement = document.querySelector('.ui-dialog.ui-overlay-visible [data-widgetvar]');
querySelector allows a CSS like selector combining class together with attribute selector.
Update:
Here is a working example:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<title>Test</title>
<script type="text/javascript">
function main() {
var myElement = document.querySelector('.ui-dialog.ui-overlay-visible [data-widgetvar]');
console.log("Attribute value", myElement.getAttribute('data-widgetvar'));
}
document.addEventListener("DOMContentLoaded", main);
</script>
</head>
<body>
<div class="ui-dialog ui-overlay-visible">
<div>some element</div>
<div data-widgetvar="someValue">some text content</div>
</div>
</body>
</html>

Related

Javascript/HTML Image Change

My task for my Javascript class is to create a script for this page that changes the image every 3 seconds. I think my code is correct, however Firebug tells me "document.getElementByID is not a function." Can someone show me what I am doing incorrectly?
This is my JS script.
<script type="text/javascript">
var i = 0
var lightArray = ["pumpkinOff.gif", "pumpkinOn.gif"]
var currentLight = document.getElementByID('light')
// ChangeLight Method Prototype
function changeLight() {
currentLight.src = lightArray[i++];
if (i == lightArray.length) {
i = 0;
}
}
setInterval(changeLight, 3000)
</script>
Here is my edited HTML code:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JavaScript for Programmers</title>
</head>
<body>
<h2>Happy Halloween!</h2>
<img id="pumpkin" src="pumpkinoff.gif" alt="pumpkin">
<script src="../Script/spooky.js"></script>
</body>
</html>
Incorrect capitalisation on
var currentLight = document.getElementByID('light')
Should be:
var currentLight = document.getElementById('pumpkin')
I have attached a working fiddle:
http://jsfiddle.net/11csf4k2/
It's a typo it should be:
var currentLight = document.getElementById('light'); //Not ID
It should be Id not ID:
document.getElementById('light');
Also note that you don't have element with id light on your page. It probably should be
document.getElementById('pumpkin');

actually creating a webpage with javascript

An extremely simple question but I am noob. I have been learning javascript and jquery for a while on jsfiddle, there everything works fine, building cool quizzes and all, but when I tried to actually create a directory, reference the jquery library and my javascript file, nothing works, even the below code, when saved as an HTML file doesn't work. I just paste it into notepad and save it as html, when I open it with it doesn'T work.
<html>
<head>
<title>webpage</title>
<script type="text/javascript">
window.onload = function() {
var myDiv = document.getElementById('#div');
myDiv.appendChild(document.createTextNode("Hi my name is Mehmetcan"));
}
</script>
</head>
<body>
<div id="myDiv"> </div>
</body>
</html>
Use this as starting point:
<html>
<head>
<script src="http://code.jquery.com/jquery-1.11.1.min.js"></script>
<title>webpage</title>
<script type="text/javascript">
$(document).ready(function () {
var myDiv = document.getElementById('myDiv');
myDiv.appendChild(document.createTextNode("Hi my name is Mehmetcan"));
});
</script>
</head>
<body>
<div id="myDiv"> </div>
</body>
Another approach that doesn't rely on JQuery but on pure, vanilla javascript.
<html>
<head>
<title>webpage</title>
<script type="text/javascript">
document.body.onload = loadSite;
function loadSite() {
var newDiv = document.createElement("span");
var newContent = document.createTextNode("Hi there and greetings!");
newDiv.appendChild(newContent);
myDiv.appendChild(newDiv);
}
</script>
</head>
<body>
<div id="myDiv"> </div>
</body>
</html>
You can find the full javascript sample as well as more information here, on the document.createElement MDN pages.
document.body.onload = addElement;
var my_div = null;
var newDiv = null;
function addElement () {
// create a new div element
// and give it some content
var newDiv = document.createElement("div");
var newContent = document.createTextNode("Hi there and greetings!");
newDiv.appendChild(newContent); //add the text node to the newly created div.
// add the newly created element and its content into the DOM
my_div = document.getElementById("org_div1");
document.body.insertBefore(newDiv, my_div);
}

manipulating tag using java script

I am fairy new in learning JavaScript , I am practising to manipulate a tag,
here is my code
I know that I am making a silly mistake here but I am not sure which part has went wrong ?
could any one please give me some hint ?
<html lang='en'>
<head>
<meta charset="UTF-8" />
<title>
HTML Hyperlinks
</title>
</head>
<body>
<h1>
HTML Hyperlinks
</h1>
<p>
Here is a link to <a name = "hyper" href="http://yahoo.com/">page</a>.
The text around the link is not part of the link.
</p>
<script>
var element = document.getElementsByTagName("a");
var attribute = element.getAttribute("href");
element.setAttribute("href","Http://google.com");
element.setAttribute("target","_blank");
</script>
</body>
</html>
getElementsByTagName says elements. Plural.
It returns a NodeList, which is like an Array, not a single Element.
You need to loop over its return value (e.g. with for) or access it by index ([0])
You are requesting a collection of a tags, but then treating them like a single entity.
<script>
var element = document.getElementsByTagName("a");
var attribute = element.getAttribute("href");
element.setAttribute("href","Http://google.com");
element.setAttribute("target","_blank");
</script>
try this
<script>
var element = document.getElementsByTagName("a")[0];
var attribute = element.getAttribute("href");
element.setAttribute("href","Http://google.com");
element.setAttribute("target","_blank");
</script>
or
<script>
var elements = document.getElementsByTagName("a");
for(var i = 0; i < elements.length; i++)
{
var element = elemenets[i];
var attribute = element.getAttribute("href");
element.setAttribute("href","Http://google.com");
element.setAttribute("target","_blank");
}
</script>
Change this line
var attribute = element.getAttribute("href");
to this
var attribute = element[0].getAttribute("href");

can any one explain and provide the correct the code?

The HTML file has:
<html>
<head>
<title>title</title>
<script style="text/css" src=".\Scripts\CSS\tryc.css"></script>
<script style="text/javascript" src=".\Scripts\JavaScripts\Text8.js"></script>
</head>
<body id="body">
<h1 id="heading1">Coming Soon</h1>
<object id="circle-svg" width="1300" height="560" type="image/svg+xml" data=".\Scripts\svg\ulti.svg"></object>
</body>
</html>
The JavaScript has
window.onload = function () {
var as = document.getElementById("body");
var as1 = as.getElementById("heading1");
as1.style.color = "blue";
alert(as1);
alert("try");
};
The text does not turn blue.
getElementById must always be called from a document object.
var as = document.getElementById("body");
var as1 = as.getElementById("heading1");
var as1 = document.getElementById("heading1");
No nested context is needed, because IDs must be unique within the document.
And FWIW, you can use document.body instead of putting an ID on the body.
Oh, also you should use forward slashes instead of backslashes to get your script.
<script type="text/javascript" src="./Scripts/JavaScripts/Text8.js"></script>
I dont think you can use
as.getElementById();
Why dont you go directly with:
as = document.getElementById('heading1');
as.style.color = 'blue';

Extract text from a div class with JQuery

I have this simple HTML code:
<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<title>Demo</title>
</head>
<body>
<script src="jquery.js"></script>
<script src="prova.js"></script>
<div class="altro"><a href=#>Div 1</a></div>
<div class="ann"><a href=#>Div 2</a></div>
<div class="ann"><a href=#>Div 3</a></div>
</body>
</html>
I would like to extract the content of the second div "Div 2" of the class "ann" using a JQuery script. I tried with:
var str = $( ".ann" ).text();
But it takes both Div 2 and Div 3. How can I extract only the one I want?
use .eq() - it takes 0 based index
var str = $( ".ann" ).eq(1).text();
or :eq()
var str = $( ".ann:eq(1)" ).text();
If you want the text from the first div with class "ann":
var str = $('.ann:first').text();
Or:
var str = $('.ann').eq(0).text();
But if you want the text inside the <a> element that is inside the first div with class "ann":
var str = $('.ann:first').children('a').text();
Or:
var str = $('.ann').eq(0).children('a').text();
Note:
- The :first selector limits the selector to the first matching element.
- The .eq() function reduces the matching set to the element with the given zero-based index.
You can try :not(:first):
var str = $(".ann:not(:first)").text();
or
var str = $(".ann").not(':first').text();
fiddle

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