We Keep Coding

Remove row from form with vanilla js

I have a form I enter student info (name, email, address) and I was able to add a new row (made of three columns) using JS after I click a button. Every time a new row is created, three new columns are created with three input boxes each with its own element ID. So far so good. However, now I can't for the life of me figure out how to remove the last row that was added. Below is my code:
var student_ids = 0;
document.getElementById("studentCount").value = student_ids;
function anotherStudent(){
document.getElementById("student_info").innerHTML +=
"<div class='section colm colm4'>"+
"<input type='text' name='stud_name_" + student_ids + "'id='stud_name_" +student_ids+ "'class='gui-input' placeholder='Student name'>"+
"</div><!-- end section -->" +
"<div class='section colm colm4'>" +
"<input type='email' name='stud_email_" + student_ids + "'id='stud_email_" + student_ids + "'class='gui-input' placeholder='Email'>" +
"</div><!-- end section -->" +
"<div class='section colm colm4'>" +
"<input type='text' name='stud_address_" + student_ids + "'id='stud_address_" + student_ids + "'class='gui-input' placeholder='Address'>"+
"</div><!-- end section -->" ;
student_ids = ++student_ids;
document.getElementById("studentCount").value = student_ids ;
}
function removeStudent(){
var x = document.getElementById('stud_name_'+student_ids);
var y = document.getElementById('stud_email_'+student_ids);
var z = document.getElementById('stud_address_'+student_ids);
x.remove();
y.remove();
z.remove();
}

Edit:
You are not removing the divs, only the inputs themselves. You are also incrementing the student_ids global variable after you insert a row. This means that the removeStudent() function will always try to remove a non-existing row.
It would be better to pass the desired student_ids to removeStudent(), or manually de-increment the value.
In older environments (such as Explorer):
You cannot directly remove DOM elements from JavaScript. It's a bit unintuitive, but you have to go to the parent of that element and remove it from there:
var element = document.getElementById('stud_name_'+student_ids);
element.parentNode.removeChild(element);

Dynamically add array contents as new elements - JQuery

edit: Problem solved! I was modifying the page before it was loaded so the script didn't actually do anything. I fixed it now and it works. Thanks for the help, I'll have to chalk this one up to being new to jQuery and it's weirdness.
Long story short I'm trying to make a webpage that dynamically takes Article titles, thumbnail images, descriptions, and links to them, and creates a nicely formatted list on the page. I'm trying to accomplish this in jQuery and HTML5.
Here is the sample data that I'll be using to dynamically populate the page. For now formatting isn't important as I can do that later after it works at all.
<script>
var newsTitles = ["If It Ain't Broke, Fix It Anyways"];
var newsPics = ["images/thumbnail_small.png"];
var newsDescs = ["August 14th 2015<br/><b>If It Ain't Broke</b><br/>Author: Gill Yurick<br/><br/> Sometimes, a solution isn't the only one. So how do we justify changes to systems that don't need to be fixed or changed? I explore various systems from other successful card games and how their approaches to issues (be they successes or failures in the eyes of the deisgners) can help us create EC."];
var newsLinks = ["it_aint_broke-gill_popson.html"];
var newsIndex = 0;
var newsMax = 1;
The section of code where I'm trying to use the contents of the arrays above to dynamically fill elements.
<td style="height:500px;width:480px;background-color:#FFF7D7;padding:20px" colspan=2 id="article">
<h1>Articles</h1>
<!-- the column for each news peice add an element with the thumbnail, the title and teh desc -->
<script>
for(i = 0; i < newsMax; i++) {
$("#articleList").append("<h3 href="" newsLinks[i] + "">" + newsTitles[i] + "</h3>", "<img src=""newsPics[i] + "">","<p>" + newsDesc[i] + "</p>", ); $("div").append("hello");
}
</script>
<div id="articleList">
HELLO
</div>
</td>
Here is what it ends up looking like, I can post more info if needed as I am aware this may not be clear enough to fully explain my problem but I am unable to determine that. Thank you in advance.

try this
for(i = 0; i < newsMax; i++) {
$("#articleList").append("<h3 href=""+ newsLinks[i] + "">" + newsTitles[i] + "</h3>, <img src=""+newsPics[i] + "">, <p>" + newsDescs[i] + "</p>" ); $("div").append("hello");
}
Concatation issue + typo for newsDescs

The following string is invalid html and is missing a +
"<h3 href="" newsLinks[i] + "">"
You need to use proper quotes for html attributes, not &quote;
Try
"<h3 href='" + newsLinks[i] + "'>"
OR
"<h3 href=\"" + newsLinks[i] + "\">" // `\` used to escape same type quote
Personally I prefer opening/closing html strings with single quotes but either will work
Note tht you should be getting a syntax error thrown in dev tools console which would have helped you locate problems

for(i = 0; i < newsMax; i++) {
$("#articleList").append("<h3 href='" + newsLinks[i] + "'>" + newsTitles[i] + "</h3>");
$("#articleList").append("<img src='" + newsPics[i] + "'>","<p>" + newsDesc[i] + "</p>" );
}

edit (append?) a string stored in a jquery variable

I am bringing a big html string inside an ajax call that I want to modify before I use it on the page. I am wondering if it is possible to edit the string if i store it in a variable then use the newly edited string. In the success of the ajax call this is what I do :
$.each(data.arrangement, function() {
var strHere = "";
strHere = this.htmlContent;
//add new content into strHere here
var content = "<li id=" + this.id + ">" + strHere + "</li>";
htmlContent is the key for the chunk of html code I am storing in the string. It has no problem storing the string (I checked with an alert), but the issue is I need to target a div within the stored string called .widgteFooter, and then add some extra html into that (2 small divs). Is this possible with jquery?
Thanks

Convert the string into DOM elements:
domHere = $("<div>" + strHere + "</div>");
Then you can update this DOM with:
$(".widgetFooter", domHere).append("<div>...</div><div>...</div>");
Then do:
var content = "<li id=" + this.id + ">" + domHere.html() + "</li>";

An alternative way to #Barmar's would be:
var domHere = $('<div/>').html( strHere ).find('.widgetFooter')
.append('<div>....</div>');
Then finish with:
var content = '<li id="' + this.id + '">' + domHere.html() + '</li>';

You can manipulate the string, but in this case it's easier to create elements from it and then manipulate the elements:
var elements = $(this.htmlContent);
elements.find('.widgteFooter').append('<div>small</div><div>divs</div>');
Then put the elements in a list element instead of concatenating strings:
var item = $('<li>').attr('id', this.id).append(elements);
Now you can append the list element wherever you did previously append the string. (There is no point in turning into a string only to turn it into elements again.) Example:
$('#MyList').append(item);

jQuery "undefined" prints when appending to html element

I'm making a jQuery MP3 player. The song structure is first generated (including the information about the song), and then the structure is appended to a div using jQuery like this:
function loadFromPlaylist(playlist) {
var songsStructure;
for (var i=0; i<playlist.length; i++) {
songsStructure +=
"<div id='song" + i + "'>" +
"<span class='mpPlaylistArtist'>" + playlist[i].artist + "</span>" +
"<span class='mpPlaylistSong'>" + playlist[i].song + "</span>" +
"<span class='mpPlaylistAlbum'>" + playlist[i].album + "</span>" +
"</div>";
}
$('#mpTracks').append(songsStructure);
}
This works perfectly except for one thing. When the items are displayed in the browser, a string ("undefined") is printed above the songs, like so:
<div id="mpTracks">
"undefined"
<div id="song0">...</div>
<div id="song1">...</div>
</div>
Googling this problem yielded alot of related problems but that didn't help me.
Does anyone know what the problem might be?

Initialize your variable to an empty string, before using it:
var songsStructure = '';
You did not set an initial value, so it is set to undefined. According to JS rules for concatination, this undefinedis then concatenated with the strings generated by the for loop leading to your result.

You have to initialize the songsStructure variable.
Write
function loadFromPlaylist(playlist) {
var songsStructure="";
and your problem will be solved.

Programmatically creating <DIV>s and problems arise

I am new to javascript and have written a piece of code (pasted below). I am trying to build a little game of Battleship. Think of that game with a grid where you place your ships and start clicking on opponents grid blindly if it will hit any of the opponents ships. Problem is I need to get a function called with the ID of the DIV to be passed as a parameter. When the DIV is programmatically created like below, what will work. This? : --///<.DIV id='whatever' onclick='javascript:function(this.ID)' /> .. I saw sth like that somewhere .. this inside html :S
the js code is: (there are two grids, represented by the parameter - who - ... size of grid is also parametric)
function createPlayGround(rows, who)
{
$('#container').hide();
var grid = document.getElementById("Grid" + who);
var sqnum = rows * rows;
var innercode = '<table cellpadding="0" cellspacing="0" border="0">';
innercode += '<tr>';
for (i=1;i<=sqnum;i++)
{
var rowno = Math.ceil(i / rows);
var colno = Math.ceil(i - ((rowno-1)*rows));
innercode += '<td><div id="' + who + '-' + i +'" class="GridBox'+ who +'" onmouseover="javascript:BlinkTarget(' + i + ',' + who +');" onclick="javascript:SelectTarget('+ i + ',' + who +');" >'+ letters[colno - 1] + rowno +'</div></td>';
if (i % rows == 0)
{
innercode += '</tr><tr>';
}
}
innercode += '</tr></table>';
grid.innerHTML = innercode;
$('#container').fadeIn('slow');
}

It sounds like what you really want is to get the div element that was just clicked on. If you just want to return the div that was clicked on, all you have to do is use "this":
<div id="whatever" onclick="function(this)"></div>
If you're actually more interested in getting the id of the div clicked on, you can do this:
<div id="whatever" onclick="function(this.id)"></div>
However, it sounds like you just want the id so that you can get the div using getElementById, and the first code snippet will help you skip that step.

Instead of creating the inner html from strings you can create it with jQuery and add event listeners like so:
$("<div></div>")
.click(function(e) {
selectTarget(i, who);
})
.appendTo(container);