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Add element to document and then remove it using Jquery

I am adding text to an element in Jquery using
$('.alert-saved').append('<br />See more like this >>')
I then show this to the user and pause.
$('.alert-saved').delay(5000).fadeOut(2000);
I would now like to remove all the text I appended.
I have tried this but it didn't work
$('.alert-saved').remove('<br />See more like this >>')

Just pass an empty HTML string argument:
$('.alert-saved').html('');
EDIT 1
If you need to keep other elements, you can use this method:
var newLine = jQuery('<br />See more like this');
jQuery(".alert-saved").append(newLine);
setTimeout(function() {
jQuery(newLine).remove();
}, 2000)
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p class="alert-saved">
<span>I wanna stay!</span>
</p>

Change your code to :
$('.alert-saved').append('<div id="divId"><br />See more like this >></div>');
And while removing you can use :
$('.alert-saved').remove('#divId');
With the help of divId you can easily remove your appended element/string from '.alert-saved'.

Check the below code it will work as expected -
$('.alert-saved').append('<div class="testing" <br />See more like this >> </div>')
$('.alert-saved').delay(5000).fadeOut(2000);
$('.alert-saved').remove('.testing')
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div class="alert-saved"></div>

You could try this also :
$('.alert-saved').next().remove();

You can wrap your element in an tagged element with a class, or a custom tag, and then delete it accordingly like:
var release_id = 'demo'
$('.alert-saved').append('<div class="added"><br />See more like this >></div>')
setTimeout(function() {
$('.alert-saved>.added').remove();
}, 5000);
Demo: https://jsfiddle.net/Lxy83r43/

Whatever you append append with a class like this and remove all at once using .remove()
Checkout the demo below
$('.yes').click(function(){
$('.alert-saved').append('<div class ="added" ><br />See more like this >>');
})
$('.me').click(function(){
$('.added').remove();
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="alert-saved">
asdasdasdas
</div>
<input type="button" class="me" value="remove"/>
<input type="button" class="yes" value="add"/>

An easy way to do this work is adding class or id to appended element.
But if you don't want to do this, you can store new elements in variable and append it using .appendTo() to html document like this:
var HTML = $("<br><a>New link</a>");
$(HTML).appendTo('.alert-saved');
When you want to remove elements, use bottom code.
HTML.remove();
var HTML = $("<br><a>New link</a>");
$(HTML).appendTo('.alert-saved');
setTimeout(function(){
HTML.remove();
}, 2000);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="alert-saved">
<a>Old link</a>
</div>

Check textarea or input have some special word in need

I want to make a coding area for my website,and I need to make it having color coded(syntax highlighting),and I Google so hard,but I still can't find the right answer for me, and here is my code now.
And I'm using Jquery
HTML:
<textarea class="CodeArea codingground">
<div class="HelloMate">
</div>
</textarea>
JS:
$(function(){
$('.CodeArea.codingground').on('input',function(){
var code = $(this).val();
if (code.indexOf('class')>=0) {
$( "textarea:contains('class')" ).css( "color", "red" );
}
});
});

This is not possible with a textarea.
You can use the <code> tag in conjunction with the contenteditable attribute. Some Javascript and you'll get what you want, even though you should consider to use a library for stuff like that.
var text = jQuery('code').text();
text = text.replace('class', '<span style="color: red">class</span>');
jQuery('code').html(text);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<code contenteditable="true">
class Blubb() {
}
</code>

Getting the text element of group_name

<div class="group_list_table_row" group_id="10">
<div class="group_name">Name of Course</div>
<div class="group_list_edit_row" style="left: 215px;">
Click me.
</div>
</div>
<script type="text/javascript">
/* This triggers when update button is clicked. */
$( ".update_group" ).click(function(event) {
var value = $(this).parent().parent().text();
alert(value);
event.preventDefault();
</script>
I was trying to get the text only of group_name class which is "Name of Course". However, the result of alert(value) also includes "Click me." and "Name of Course". Need help on this.

You can do this easier:
<script type="text/javascript">
/* This triggers when update button is clicked. */
$( ".update_group" ).click(function(event) {
var value = $('.group_name').text();
alert(value);
event.preventDefault();
});
</script>

Try this:
$(".update_group").click(function(event) {
var value = $(".group_name").text();
alert(value);
event.preventDefault();
});

as long as the previous answers provide a proper solution you might be interested why yours does not work, and this is because the ".group_name" element is not a parent of the parent of your element, as you might expected. It is apparently not a parent at all, containing only plaint text inside.
Therefore the $(this).parent().parent() call returns the ".group_list_table_row" element, that contains the two other divs and it's text is the concatenation of their contents.
A some indentation and things will be obvious:
<div class="group_list_table_row" group_id="10"> /*parent 2*/
<div class="group_name">Name of Course</div>
<div class="group_list_edit_row" style="left: 215px;"> /*parent 1*/
Click me.
</div>
</div>

Show/Hide a form in JavaScript

I'm trying to hide and show "form1". But even simply hiding doesn't work.
Where is the mistake?
<body>
<script type="text/javascript">
document.getElementById("F1").style.visibility = "hidden";
</script>
<form id="F1" name="form1">
<p class="style14">blah-blah
<input type="text" size="1" name="rd"> blah
</p>
</form>
</body>

Firstly you need to make sure your script tag is at the bottom of the body or use the DOMContentLoaded event
like so
document.addEventListener('DOMContentLoaded', function(){
var form = document.getElementById('F1');
form.style.visibility="hidden";
// OR
form.style.display = 'none';
});
Your F1 needs to be a string, right now you're referring to a undefined variable.
And I also recommend using display instead of visibility
#update to comment.
The opposites of them are
visibility: visible;
AND
display: block; // Or whatever

This line is wrong
document.getElementById(thediv).style.visibility="hidden";
What is "thediv" you should use :
document.getElementById("F1").style.visibility="hidden";

Try document.getElementById("F1").style.visibility=hidden;

F1 should be wrapped in quotes. You also might need to encompass your code within the onload function
window.onload = function(){
document.getElementById("F1").style.visibility = "hidden";
}

ID of draggable

I want to get the id of the div i am moving.
I have tried different methods, nothing worked.
So why isn't this working?
$('#content').children().draggable({
drag: function (event, ui) {
var id = $(this).attr("id");
$('#textarea').val(id);
}
http://jsfiddle.net/pX2T4/

This doesn't work because you are not finding the id of $('#content'), but of the child div, which does not have an id set. Thus, give the child an ID and it will find that one.

It's because $(this) is refering to the inner div marked with the class
see http://jsfiddle.net/pX2T4/
<div id="content">
<div class="content" id="foo">
<textarea name="" id="textarea" cols="30" rows="10"></textarea>
</div>
</div>
$('#content').children().draggable({
drag: function (event, ui) {
var id = $(this).attr("id");
console.log(id);
console.log($(this));
$('#textarea').val(id);
}
});
outputs "foo"

Instead $(this) use $("#content")
Try this:
http://jsfiddle.net/pX2T4/4/