I have no idea why this isn't working. I mean as far as I know It should print my array in alphabetical order to the div "output"
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title> Lexicographic ordering </title>
<script src="http://code.jquery.com/jquery-latest.min.js"></script>
<script>
var words = [];
var input = prompt("Please enter a word or type end to stop prompts");
while (input != 'end') {
words.push(input);
input = prompt("Please enter a word or type end to stop prompts");
}
words.sort();
getElementById('#output').innerHTML= words.join();
</script>
</head>
<body>
<header>Lexicographic Ordering </header>
<hr>
<div class ="page-wrapper">
h1> Lexicographic Ordering </h1>
<div id="output"></div>
</div>
</body>
</html>
There are two small bugs in your code, and they're both in this line:
getElementById('#output').innerHTML= words.join();
getElementById is not a part of the window, it's a part of the document object, so you must reference it properly. Also, that method takes an ID, not a selector, so you don't need the # in front of it.
document.getElementById('output').innerHTML= words.join();
That should do what you want! Alternatively, since I notice you have jQuery included, you could do $('#output').innerHTML = ... to achieve the same effects.
You may also try to move the <script> block at the end, just before closing of the </body>. Anywhere after the <div id="output"></div>.
JavaScript on some browsers fails when they have to reference some elements which has not been parsed by their HTML parser when the script is executing or trying to reference them.
Also, you don't use # with getElementById(...);. # is used with Jquery. This is pure JavaScript. Make it getElementById('output').whatever...;
Edit:
Another option suggested by Patrick Evans is to move the JavaScript Code in an onload() event handler method to execute the code. This ensures that the HTML is fully loaded in the DOM before we try to manipulate it.
Related
I am a complete beginner to javascript. I am also new to this website. I am asking for help to complete an assignment. I have been trying for more than 4 hours by looking at lecture material and online for a solution. It is causing me a lot of unnecessary stress. Before javascript we only used CSS and Html. I was given 6 javascript tasks to manipulate the html file (taskc.html) already given to me.
The tasks are as follows
Make a statement to change contents of h1 from "Welcome" to "Text"
2nd statement should make an new alert window when the page loads that delivers a message explaining what the page is about
3rd statement should change the title to "text"
4th statement should log the contents (innerHTML) of the first paragraph element in the console.
5th statement should hide the contents of the second paragraph when the page loads
6th statement should change the contents of the header to have a new colour of your choice
Here is that html.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Task C - The Document Object Mode</title>
</head>
<body>
<h1 id="header">Welcome</h1>
<p id="first">This site uses JavaScript</p>
<p id="second">Javascript is very useful</p>
</body>
</html>
Because the actual coding im meant to add is meant to be in the .js file I was given. so I figured I had to link the js file in the html file so I added
<script type="text/javascript" src="taskc.js"></script>
With that out of the way I went to the lecture notes and I thought I would simply need to modify some of the code given to me there like
document.getElementById('demo').innerHTML = 'Hello World!';
When I put this code in brackets I got the error (document is not defined)
I modified it to match the requirements for task 1
here it is
document.getElementById('header').innerHTML = 'text';
I was confused because I didn't know what this error meant and of course Errors and how to fix them are never explained so I had to lookup how to resolve the error.
I found that to fix it I have to declare it as a variable so I ended up doing this.
var document = 'taskc.html';
When I did this for document, alert and console all the errors went away, but when I did a live preview only statement 1 was working
If anyone could help me fix this I would really appreciate because I don't understand enough javascript to be able to complete this in a reasonable amount of time.
So first: Please use Javascript functions to keep your code tidy and clean.
Example:
HTML:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Task C - The Document Object Mode</title>
</head>
<body>
<h1 id="header">Welcome</h1>
<p id="first">This site uses JavaScript</p>
<p id="second">Javascript is very useful</p>
<script type="text/javascript" src="taskc.js">test();</script>
</body>
</html>
function test(){
alert("This is a test!");
}
Always implement scripts that are document referenced at the bottom of your html.
If you use JQuery you can use following code to check document is loaded:
$(document).ready(function(){
//foo bar
});
Im new to Javascript and this site. Below are 2 codes (only HTML, normal i work with external js files) which deliver a button what you can click for a date. I was wondering which code has the preference amongst the developers and is there any advantage from 1 another? The way i see it is that adding a function is overkill.
Code 1
<!DOCTYPE html>
<html>
<head>
<title>Test</title>
<meta charset="utf-8">
</head>
<body>
<button onclick="document.getElementById('demo').innerHTML = Date()">The time is?</button>
<p id="demo"></p>
</body>
</html>
Code 2
<!DOCTYPE html>
<html>
<head>
<title>Test</title>
<meta charset="utf-8">
</head>
<body>
<button onclick="myFunction()">The time is?</button>
<p id="demo"></p>
<script>
function myFunction() {
document.getElementById("demo").innerHTML = Date();
}
</script>
</body>
</html>
The second one is way better, you are separating the js from the html.
If you have two buttons with the same function, it will be easier to avoid duplicated code and to maintain with the second version!
For example if you want to change the behaviour of your buttons, you won't have to modify your html and be able to change the beviour every where at once.
In my opinion the correct answer here is neither of both.
To write maintainable and readable code, the best practice is to have a complete separation between HTML, CSS and JavaScript. Making the assumption that "it's only one line", is pretty dangerous, as one line quickly becomes two and so on. It's better to always use the same rules instead of making exceptions for one-liners.
Personally, I would write HTML like this:
<button class="time-button"></button>
<p id="demo"></p>
<script src="script.js"></script>
In script.js, you can then attach an event listener like this:
// Note that querySelector might not be supported in really old browsers
var timeButton = document.querySelector('.time-button');
var demoParagraph = document.getElementById('demo');
// Or attachEvent for IE < 11
timeButton.addEventListener('click', timeFunction);
/**
* Here you can write some beautiful comments about the function
*/
function timeFunction (eventData) {
demoParagraph.innerHTML = new Date().toISOString();
}
In case you write it like that you can start listening (addEventListener) and stop listening (removeEventListener) whenever you want to.
It's recommended to put the elements in a variable, since looking up an element is pretty slow.
I'd say :
Both are correct depending on what you want to do with it.
First way : OK if the function is short and not complex, no re-use purpose.
Second way : OK if the function is complex, need to be maintained and plus : you can re-use it and avoid code duplication.
Now another approach is to extract javascript methods in another .js file.
I'm learning xss prevention through this ppt:http://stash.github.io/empirejs-2014/#/2/23, and I have a question on this page.
It says "JavaScript sanitization doesn't save you from innerHTML", and I tried a simple test like this:
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>test</title>
</head>
<body>
<div id="test"></div>
<script>
var userName = "Jeremy\x3Cscript\x3Ealert('boom')\x3C/script\x3E";
document.getElementById('test').innerHTML = "<span>"+userName+"</span>";
</script>
</body>
</html>
when I opened this html on my browser(chrome), I only saw the name "Jeremy",by using F12, I saw
<div id="test"><span>Jeremy<script>alert('boom')</script></span></div>
Although the script had been added to html, the alert box didn't come out.
"JavaScript sanitization doesn't save you from innerHTML" I think this means that the word "boom" should be alerted. Am I right?
According to MDN, innerHTML prevents <script> elements from executing directly1, which means your test should not alert anything. However, it does not prevent event handlers from firing later on, which makes the following possible:
var name = "\x3Cimg src=x onerror=alert(1)\x3E";
document.getElementById('test').innerHTML = name; // shows the alert
<div id="test"></div>
(script adapted from the example in the article, with escape sequences although I'm not sure those are relevant outside of <script> elements)
Since <script> elements never execute when inserted via innerHTML, it's not clear to me what that slide is trying to convey with that example.
1 This is actually specified in HTML5. MDN links to a 2008 draft; in the current W3C Recommendation, it's located near the end of section 4.11.1, just before section 4.11.1.1 begins:
Note: When inserted using the document.write() method, script elements execute (typically synchronously), but when inserted using innerHTML and outerHTML attributes, they do not execute at all.
First, some of you may notice that I reposted this question after deleting it. This is because it was mistakenly marked as a duplicate by someone who didn't bother to check - the question he linked to was about an <input> element; that solution does not work for textareas.
Anyway, consider the following code:
<!DOCTYPE html>
<html>
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js" type="text/javascript"></script>
<script type="text/javascript">
function caek() {
$('textarea[name=txt1]').val("cake");
$('textarea[name=txt1]').focus();
}
</script>
</head>
<body>
<div id="bar"></div>
<form name="frm1" id="cake">
<textarea name="txt1"></textarea>
</form>
<input type="button" value="Activate"
onclick="caek()">
</body>
</html>
When you run that, you will notice that the cursor is pushed to the start of the textarea, before the text. How can I make it come after all the text, at the end of the textarea? A non-inline solution would be optimal, but anything will do.
And a standalone solution (no plugins etc) would be perfect.
This is working for me.
function caek() {
txtArea = $('textarea[name=txt1]');
txtArea.val("cake");
txtArea.focus();
tmpStr = txtArea.val();
txtArea.val('');
txtArea.val(tmpStr);
}
This works.
$ta.text($ta.text()).focus()
Demo: http://jsfiddle.net/elclanrs/WWsBa/
You can use the rangyinputs jQuery plugin to do this in a cross platform way.
There's a demo here:
http://rangyinputs.googlecode.com/svn/trunk/demos/textinputs_jquery.html
Set the start and end to the same number and it'll set the cursor to that point (though it doesn't focus the textarea, so you have to tab into it to see the effect). In your case, you'd want to set it to the length of the text.
I want to replace the current script tag with the HTML contents generated by the same script.
That is, my Page is
<html>
<body>
<div>
<script src="myfile1.js"></script>
</div>
<div>
<script src="myfile1.js"></script>
</div>
</body>
</html>
Inside each .js file corresponding html contents are generated. I want to put the contents as the innerHTML of the parent div. But can't set id for the parent div because the page is not static. So the current script tag must be replaced with the HTML content. How can I do this?
For each script tag src is the same. So can't identify with src. These scripts displays
some images with text randomly. Scripts are the same but displays different contents in divs on loading
Please help me
try inside of myfile1.js:
var scripts = document.getElementsByTagName( "script" );
for ( var i = 0; i < scripts.length; ++ i )
{
if ( scripts[i].src == "myfile1.js" )
{
scripts[i].parentNode.innerHTML = "new content";
}
}
This is a great question for those trying to implement a JSONP widget. The objective is to give the user the shortest possible amount of code.
The user prefers:
<script type="text/javscript" src="widget.js"></script>
Over:
<script type="text/javscript" src="widget.js"></script>
<div id="widget"></div>
Here's an example of how to achieve the first snippet:
TOP OF DOCUMENT<br />
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
// inside of widget.js
document.write('<div id="widget"></div>');
$(document).ready(function() {
$.getJSON('http://test.com?remote_call=1', function(data) {
$('#widget').html(data);
});
});
<br />BOTTOM OF DOCUMENT
Have a look at: http://alexmarandon.com/articles/web_widget_jquery/ for the correct way to include a library inside of a script.
document.currentScript has been available since 2011 on Firefox and 2013 on Chrome.
document.currentScript documentation at MDN
<!DOCTYPE html>
<meta charset="UTF-8">
<title>currentScript test</title>
<h1>Test Begin</h1>
<script>
document.currentScript.outerHTML = "blah blah";
</script>
<h1>Test End</h1>
Unfortunately a running JavaScript file is not aware of where it is running. If you use document.write() in the script, the write function will take place wherever the script runs, which would be one way to accomplish what you want, but without replacing the contents or being able to perform any actions on the enclosing DIV.
I can't really envisage a situation where you'd have such stringent restrictions on building a page - surely if the page is dynamic you could generate identifiers for your DIV elements, or load content in a more traditional manner?
Why not use Smarty?
http://www.smarty.net/
You can use javascript in Smarty templates, or just use built-in functions.
Just take a look at http://www.smarty.net/crash_course
poof -- old answer gone.
Based on your last edit, here's what you want to do:
<html>
<head>
<!-- I recommend getting this from Google Ajax Libraries
You don't need this, but it makes my answer way shorter -->
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
function getRandomContent(){
// I expect this is the contents of your current script file.
// just package it into a function.
var rnd = Math.random();
return "[SomeHtml]";
}
$('.random').each(idx, el){
$(this).html(getRandomHtmlContent());
});
});
</script>
</head>
<body>
<div class="random">
</div>
<div class="random">
</div>
</body>
</html>
If you don't mind the script tag remaining in place you can use something as simple as document.write().
myfile1.js:
document.write("<p>some html generated inline by script</p>");
It will do exactly what you need.