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Replace html with html using Javascript

I want to replace a big section of html code (the content on the side) with other html code.
I have used the JavaScript code below:
document.getElementById("content").innerHTML = "";
The thing is that I can't replace html code that got the "" characters in it. Can someone please help me?
I should ad that I´m a beginner with JavaScript and as of now I want to stay away from jQuery.

try with
document.getElementById("content").innerHTML ='text to be replaced with "" ';
or with
document.getElementById("content").innerHTML ="text to be replaced with \"\"";
or with
document.getElementById("content").innerHTML ='text to be replaced with \'\'';
( \" is the escape sequence for the character " and in javascript you can use either ' or " for the strings)
here the jsfiddle sample

Single quotes inside single quotes cause error

I have this code:
<span onmouseout="tooltip.hide();" onmouseover="tooltip.show('Hello. This is a simple tooltip, I'm here if you need me, we've been away for some time.');" class="hotspot">test link</span>
the thing is that the SINGLE quote ' is causing the tooltip not to show... so I mean IF the text contains ' the tooltip will not show... because all the text is already inside single quotes...
Can someone please help me to fix this?

Try setting the tooltip text to a var and then doing a replace on the single quote with '
var tooltip = tooltip.replace(/'/g, "'");

Fixed this myself.
So I just replaced every instance of ' to \' in str_replace function :)
WAS:
$desc = str_replace('"', "", preg_replace('/(\s\s+|\t|\n)/', ' ', JFilterOutput::cleanText($regs[0])));
IS NOW:
$desc = str_replace("'", "\\'", preg_replace('/(\s\s+|\t|\n)/', ' ', JFilterOutput::cleanText($regs[0])));

Use ’ for Special Characters in HTML.
<span onmouseout="tooltip.hide();" onmouseover="tooltip.show('Hello. This is a simple tooltip, I’m here if you need me, we’ve been away for some time.');" class="hotspot">test link</span>
I created Working Demo with alert() you can run this code snippet :)
<span onmouseover="alert('Hello. This is a simple tooltip, I’m here if you need me, we’ve been away for some time.');"
class="hotspot">test link</span>

HTML and JavaScript - How to save plain text right

I want to save a locally generated textfile.
This code almost does what I want:
<a download="filename.txt" href="data:text/plain,sometext">Download</a>
sometext represents a string in that tag attribute (inserted using javascript).
You could imagine it as the content of a textarea which is set by the user.
The problem is that sometext must not contain " or ' because otherwise the href attribute thinks that its content finishes earlier which causes the tag to just save a part of that string when you click on it.
As sometext is generated by the user, it can contain these characters and I do not want to force the user to not use these.
Is there another way to save text files using html/javascript?
I do not want to send sometext to the server. (Which would solve the problem because I could create a file there (including " and ') and feature a download link)

It will depend on how are you adding this something to the href.
First of all, a single quote wont matter, because it is wrapped by double quotes ", so it will work well like this:
Download
When it comes to double quotes, in the HTML context you would have to use the correct notation, in this case it would be ". The HTML will understand it as double quotes:
Download
<!-- It will turn into mytext"text -->
However
Since you said that it will be an user's input, I suppose you might be setting the href through Javascript, so I don't think it would matter, it would be like this:
(Try typing single or double quotes... For JS it won't matter)
var ChangeHref = function() {
var el = document.getElementById("a1");
el.href = "data:text/plain," + document.getElementById("inp1").value;
}
<input id="inp1" type="text" />
<input type="button" value="change href" onclick="ChangeHref()" />
<br />
<a id="a1" download="filename.txt" href="data:text/plain,test">Download</a>

Write a simple javascript to remove ' and " characters like so
userText.replace(/\'/g, '').replace(/\"/g, '');
The / means its a regex, the \' and \" represent the literal characters ' and " and the g at the end makes it find all to occurrences to replace.
But since you want to keep it then do this:
userText.replace(/\'/g, '\\\'').replace(/\"/g, '\\\"');
The \ is a literal backslash. that way when you add it to the name of the file it will escape out and mean a literal ' and ".

HTML textarea ignores 1st new line character, why?

Could you explain why this:
<script type="text/javascript">
document.write("<textarea cols='10' rows='10'>" + "\nhello\nbabe\n" + "</textarea>");
</script>
renders a textarea with one new line at the bottom, but NO new line at the top?
Tested IE8, FF11, Safari 5.1, Chrome 24
And it's not a JS issue, even when you write HTML in page you get the same result, i.e.
<textarea cols='10' rows='10'>
hello
babe
</textarea>
The 1st new line is still missing!!!
I need to add another new line at the top in order to show one:
document.write("<textarea cols='10' rows='10'>" + "\n\nhello\nbabe\n" + "</textarea>");

When writing inside of XHTML use proper entities.
<textarea>
hello</textarea>
If a text node begins with white space (space, new line) it will be ignored by HTML parsers. Encoding the new line into a proper HTML entity forces the parser to acknowledge it.
== carriage return

Answering the question "Why". This is specified in HTML 5 specification in the chapter that describes how DOM tree is created from tags found in a HTML document.
In the current HTML 5 living standard it is "12.2 Parsing HTML documents" > "12.2.6 Tree construction" > "12.2.6.4 The rules for parsing tokens in HTML content" > "12.2.6.4.7 The "in body" insertion mode".
(In HTML 5.2 the same section is numbered 8.2.5.4.7).
Scroll down for item "A start tag whose tag name is "textarea""
A start tag whose tag name is "textarea"
Run these steps:
1. Insert an HTML element for the token.
2. If the next token is a U+000A LINE FEED (LF) character token, then ignore that token and move on to the next one. (Newlines at the start of textarea elements are ignored as an authoring convenience.)
3. Switch the tokenizer to the RCDATA state.
...
The algorithm deals with LF characters only, because CR characters are handled earlier.
(Historically, looking into obsolete HTML 4.01 specification:
Its Chapter 17.7 "The TEXTAREA element" has an example that shows that text content for a textarea starts from a new line.
Appendix B.3.1 Line breaks (informative) explains that such behaviour originates from SGML.)
A line break character before </textarea> end tag is not ignored nowadays, in HTML 5.

If possible, change your code to have the textarea pre-defined as html, then write the string like this instead:
HTML:
<textarea cols='10' rows='10' id='test'></textarea>
Script:
document.getElementById('test').innerHTML = '\nhello\nbabe\n';
That should preserve white-space. Optionally you can add a css rule:
textarea {
white-space:pre;
}
A fiddle to play with:
http://jsfiddle.net/RFLwH/1/
Update:
OP tested in IE8 which this does not work - it appear to be a limitation/bug with this browser. IE8 do actually use CR+LF if you manually insert a line-feed at the top, but when set programmatic this is completely ignored by the browser.
Add this to the html to do a test:
<span onclick="this.innerHTML = escape(document.getElementById('test').innerHTML);">
Get textarea content
</span>
You can see the string returned is:
%0D%0Ahello%20babe%20
meaning the CR+LF is there (the other line-feeds are converted to spaces - but inserting a space at the beginning does not help either). I guess there is nothing you can do about this behavior; the browser is obsolete (but unfortunately still widely used so this can be a problem for those users if this is essential).

Add a whitespace before the first "\n" like this :
<script type="text/javascript">
document.write("<textarea cols='10' rows='10'>" + " \nhello\nbabe\n" + "</textarea>");
</script>
or
<textarea cols='10' rows='10'> <!-- whitespace here -->
hello
babe
</textarea>
otherwise it won't work.
Update:
Later in your server side, you can remove the first whitespace by doing
$str = ltrim ($str,' ');
or
$str2 = substr($str, 4);
if it is PHP.

It should be a \n\r at the top:
document.write("<textarea cols='10' rows='10'>" + "\n\rhello\nbabe\n" + "</textarea>");
jsbin

Finally i finished with this server-side solution:
to double leading(only first!) nl symbol before output it in textarea:
if(str_startswith("\r\n",$value))
{
$value = "\r\n".$value;
}elseif(str_startswith("\n",$value))
{
$value = "\n".$value;
}elseif(str_startswith("\r",$value))
{
$value = "\r".$value;
}
function str_startswith($start, $string)
{
if(mb_strlen($start)>mb_strlen($string))
return FALSE;
return (mb_substr($string, 0,mb_strlen($start))==$start);
}

Apostrophes in jquery/javascript string

I have the following code which appends an icon with an alert after the <a> tag :
$j("li[name='"+node_name+"'] > a").after('<a onmouseover="alert(\' expnote_from_db[n][0] \');" ><ins class="' + selected_class + '"> </ins></a>');
The code above works fine except that it displays exp_from_db[n][0] as a string inside the alert box.
So I changed it to the code below but nothing is displayed now
$j("li[name='"+node_name+"'] > a").after('<a onmouseover="alert(\'"'+ expnote_from_db[n][0] + '"\');" ><ins class="' + selected_class + '"> </ins></a>');
I don't understand where did I go wrong with the apostrophes.
I would appreciate your help regarding this. Thanks

This should work
$j('li[name="'+node_name+'"] > a')
.after('<a onmouseover="alert(\''+ expnote_from_db[n][0] + '\')" ><ins class="' + selected_class + '"> </ins></a>');

The " characters are delimiting the HTML attribute. You are terminating that attribute prematurely.
<a onmouseover="alert(\'"
Nesting JavaScript in HTML attributes is a pain.
Nesting JavaScript in HTML attributes in JavaScript strings is a bigger pain.
Don't do it. Apply event handlers using addEventListener and friends (since you are using jQuery that means using the on method which abstracts them).