Develop Reference

I'm trying to set a generic element invisible by attribute and in one line of javascript

I'm limited to one line because of a Chrome Extension and it's the only one that fits my needs.
The <td> needs to be gone through to the attribute "UserName" to determine if a blocked user needs to be invisible.
I cannot figure this out and I'm really a noob when it comes to Javascript (not my language)
I've tried display:none hidden and style.visibility="hidden".
I've tried w3Schools and searched through Javascript and HTML pages for how to this and while I've got code that does work, it's a script that takes about 8 lines which doesn't work. I may have to ditch it but I figured I've give it one last shot.
document.getElementsByTagName("td")[0].getAttribute("theUserName").value("madmax").style.visible = "hidden";
Expected - The <td> should not show up
Results - It shows up

One line to hide the content:
[...document.querySelectorAll("td[theUserName=madmax]")].forEach(e=>e.style.display = 'none');
To remove the <td>:
[...document.querySelectorAll("td[theUserName=madmax]")].forEach(e=>e.remove());

I am assuming that you to iterate through all <td> elements to search for one with theUserName attribute with value madmax, then make that element invisible. That can be achieved with:
for(TdElement of document.getElementsByTagName("td")) {
if (TdElement.getAttribute("theUserName") == "madmax") {
TdElement.style.visiblity = "hidden";
}
}
Condensed to a single line, this is:
for(TdElement of document.getElementsByTagName("td")) if TdElement.getAttribute("theUserName") == "madmax") TdElement.style.visiblity = "hidden"

Shrinking a Table in JavaScript

Never used JavaScript Before and I'm trying to fix this form in share point.
I want this text box to be small (like 1 row), until the user clicks it and then it should expand into a larger text box with like 10 rows. I apologize if this has been answered before, I don't even know what I should be looking for. Here is code I have that doesn't work, but does pop up an error message(I did not write this code):
alert(DescriptionID);
document.getElementById(DescriptionID).addEventListener("onmouseover", function(){
document.getElementById(DescriptionID).rows= "10";
});
document.getElementById(DescriptionID).addEventListener("onmouseout", function(){
document.getElementById(DescriptionID).rows= "1";
});
EDIT:
Here is what the current code will display:
EDIT2:
Thanks to a ton of help from you guys/gals I am close to finished! I can now understand it significantly better at least! Here is a picture of the code. The object is actually an "ms-formbody" ???
AND ANOTHER EDIT:
So here is the error i'm getting after using Johhny's code:

If you are using jQuery, this might work for you:
HTML:
<textarea id="expandingTextarea" rows="1">Enter Text</textarea>
JavaScript:
$(document).ready(function() {
$('#expandingTextarea').on('mouseover', function() {
$(this).attr('rows', '10');
});
$('#expandingTextarea').on('mouseout', function() {
$(this).attr('rows', '1');
});
});
I created an example here.
Update:
Using a click event to change/toggle to row count:
$(document).ready(function() {
$('#expandingTextarea').on('click', toggleExpand);
function toggleExpand() {
var oldRowCount = $(this).attr('rows');
var newRowCount = parseInt(oldRowCount) === 1 ? 10 : 1;
$(this).attr('rows', newRowCount);
}
});
Demo here.

In fact, you don't need JS to achieve what you want. CSS can do it for you.
<!--html-->
<textarea class="descr">This is description</textarea>
/*css*/
.descr {height: 20px;}
.descr:hover, .descr:focus {height: 120px;}

alter the height instead of the "rows" property.
open up the page in chrome, open the developer tools (View->Developer->Developer Tools) and then use "inspect" to select the text area you want to manipulate.
try playing around with the css of that element. then, write your javascript to change just the property that you want.
https://developer.chrome.com/devtools

The code you showed looks fine but DescriptionID should contain the ID of the description box. You can check what it is by right clicking on the description form and clicking "inspect element". Then assign var DescriptionID = "someID" at the beginning of the code.
Also, you might consider altering the height, not the rows.
If the form doesn't have an ID, look for an option to change the HTML and add one. If you don't have such an option, it's still possible to achieve what you want to do but you have to look beyond getElementById.

How to bind to 'inview' event on multiple elements

I'm playing around with Velocity.js and jquery.inview, and I want all the titles on my page to slideDownIn when they come into view. This code works fine for the first title:
$('.movies-title').bind('inview', function(event, isInView, visiblePartX, visiblePartY) {
if (isInView) {
// element is now visible in the viewport
if (visiblePartY == 'top') {
// top part of element is visible
} else if (visiblePartY == 'bottom') {
// bottom part of element is visible
} else {
// whole part of element is visible
$(this).velocity("transition.slideDownIn", 500);
}
} else {
// element has gone out of viewport
$(this).velocity("reverse");
}
});
If I copy and paste the above several times and replace .movies-title with the classes of the other titles, it works as I want it to.
However, that seems like a lot of extra code. I tried changing $('.movies-title') to $(.movies-title, .tv-title, .books-title) but then the animation only works for the last element in the list. I also tried adding a new class called .title to all of the titles and changing .movie-title to .title but that didn't work either.
What am I doing wrong? How can I condense the code?

The best solution is to use a single class on each of these elements since they have something so in common. You might just add title as a class type and apply it to that class.
<div class="title movie-title"></div>
I know you mentioned this in your question, but I can't see why this wouldn't work.

Try using delegate instead of bind for multiples. Also make a unified class for all of them (I just used title)
so like this -
$('body').delegate('.title','inview', function(event, isInView, visiblePartX, visiblePartY) {
Edit - sorry linked wrong fiddle initially
see fiddle http://jsfiddle.net/d1g7sLxq/3/

Text not changing in jQuery

I seem to be doing something wrong in the following code: http://jsfiddle.net/yunowork/qKj6b/1/
When you click next, the text within the span .hiddentext should be displayed in the span .showtext on top and correspond to the right Race (Rn). For example when R3 is highlighted the content of that .hiddentext "Race 3Oregon 14:30" should be displayed within the span .showtext.
This is the line where I make a mistake:
$('.showtext').text($('.hiddentext').first('td:first').text());
What am I doing wrong here?

Let's start simple:
Your problem:
$('.showtext').text($('.hiddentext').first('td:first').text());
you are saing, that, grab all .hiddentext, choose the first that has a td ... witch is not what you have in code, you have, td that contains hiddentext... so, the other way around.
What you want to do is simply get the current NEXT td and grab the hiddentext, so, just change to:
$('.showtext').text($nextCol.find('.hiddentext').text());
Now, can you see that the <br/> is not correctly rendered? That's because you are setting the text property, and you should set the html property.
the final code should be something like:
$('.showtext').html($nextCol.find('.hiddentext').html());
live example: http://jsfiddle.net/qKj6b/8/
Your code:
every time you need to have placeholders to provide some data to a context, please, DO NOT USE HTML TAGS to hold such values and hide them... make the use of the data- attribute, witch is a HTML5 complience, and works very well in any browser even if it does not have not HTML5 support, like IE6.
your table definition (td) that currently is:
<td class="visible" id="r2">
<span class="hiddentext">Race 2<br />Santa Fe 12:00</span>
<strong>R2</strong>
</td>
should be something like:
<td class="visible" id="r2" data-text="Race 2<br />Santa Fe 12:00">
R2
</td>
witch is way easier to read, and from your javascript code, you can easily get this as:
var hiddenText = $nextCol.data("text");
Your code (part 2):
This one is quite simple to know
Every time you are repeating yourself, you're doing it wrong
You have the methods for Next and Prev almost exactly as each other, so, you are repeating everything, for this, you should refactor your code and just use one simple method, this way, any future change only happens in one place, and one place only.
$(".next").click(function(e){
e.preventDefault();
var $nextCol = $('.highlighted').next('td');
MoveCursor($nextCol, 'next');
});
$(".previous").click(function(e){
e.preventDefault();
var $prevCol = $('.highlighted').prev('td');
MoveCursor($prevCol, 'prev');
});
function MoveCursor(col, side) {
var maxCol = 8;
if((side === 'next' && col.length != 0) ||
(side == 'prev' && col.length != 0 && col.index() >= maxCol)) {
$('.highlighted').removeClass("highlighted");
col.addClass("highlighted");
// show current title
$('.showtext').html(col.data('text'));
if (col.hasClass("invisible")) {
col.removeClass("invisible");
col.addClass("visible");
var $toRem;
if(side == 'prev')
$toRem = col.next('td').next('td').next('td').next('td').next('td').next('td');
else
$toRem = $nextCol.prev('td').prev('td').prev('td').prev('td').prev('td').prev('td');
$toRem.removeClass("visible");
$toRem.addClass("invisible");
}
}
}
Live Example: http://jsfiddle.net/qKj6b/22/

It should be
$('.showtext').html($('.highlighted .hiddentext').html());
Similar for the prev link...
or even better, thanks to #balexandre:
$('.showtext').html($nextCol.find('.hiddentext').html());
$('.showtext').html($prevCol.find('.hiddentext').html());
Fiddle
Update to match #balexandre hint: Fiddle 2

Do the following:
var $currCol = $('.highlighted'); //to get the current column
$('.race strong').text($currCol.closest('.highlighted').first('td:first').text());

.hiddentext class selects all the spans and the first() will always return you the first td.
Just make sure you select .hiddentext from the currently highlighted column and you are good to go.
$('.showtext').text($('.highlighted .hiddentext').first('td:first').text());

Try this (Same for both)
$('.showtext').html($currCol.find('span.hiddentext').html());
Working Example.

javascript - check if a div is empty

I have the following setup:
<div id="whatever">
<!-- Here some dynamic divs will be loaded -->
</div>
I need to know when the "whateverdiv" has nothing inside. The catch is that when I say nothing I mean if user sees nothing. So if inside the div something like
<div style="display: none">LOOOONG TEXT</div>
is loaded I consider it empty.
If is full of blank spaces is also empty, etc... if user doesn't see anything in it is empty.
Since there are too many cases to cover (content with height 0, content with display none, blank spaces, tabs, hidden inputs etc... almost anything may be loaded there depending on situations) I tried to use the height attribute to see if has content (the div expands depending on content). This idea worked ok but now I have another problem: I must add display: none on it sometimes. When I do that the height is always load as 0. I can't use visibility because div has 10px padding that I don't want to see when is not shown. So I'm back to square one... finding some sort of way to see if a div is empty in all that cases.
Any idea how should I do that?

var d = $('#myDiv');
var empty = d.text().trim().length === 0 || !d.is(':visible');

This one should work.
http://jsfiddle.net/fedmich/SmRnT/
I'm cleaning the html comments via Regex
$(function() {
var w = $('#whatever').clone();
w.find(':hidden').remove();
var html = w.html();
html = html.replace(/<!--.*-->/g,'')
html = $.trim(html);
alert( html );
});​
To summarize
clone the object
remove hidden elements
remove html comments
$.trim( )

If you dont count whitespace as if something is not empty:
$("selector").is(":empty")
OR
$("selector").contens().length
Does the trick.
If you dont want to count text nodes as empty:
$("selector").children().length
See:
http://api.jquery.com/empty-selector/
http://api.jquery.com/contents/
http://api.jquery.com/children/