Develop Reference

create an input using parseMath() in jqmath

I’ve to create a custom text field which is support some of the mathematical expression also. So I thought of using JQMath.
I’ve to pass a expression with html input field using javascript. It’ll be added dynamically. So I put the expression in a string which is changeable anytime. But if I use the string, it didn’t give the positive output. I googled a lot about this, but I cant get it. Please help me on this.
Below is my code.
var string = "$x={-b±√{b^2-4ac}}/{2a\html'<input size=1 >'}$"
var di = document.createElement("div");
di.innerHTML = string//+textStr;
document.body.appendChild(di);
M.parseMath(di)

The \ in the javascript quoted string source needs to be doubled \\ to produce a \ in the actual string. Alternatively, jqMath also supports ` backquote for its macros, to avoid this annoyance.
Jan, the library does support mathematical Unicode characters, and the main jqMath page at http://mathscribe.com/author/jqmath.html has a table to help you find and type them.

what kind of encoding is this?

I've got some data from dbpedia using jena and since jena's output is based on xml so there are some circumstances that xml characters need to be treated differently like following :
Guns n ' Roses
I just want to know what kind of econding is this?
I want decode/encode my input based on above encode(r) with the help of javascript and send it back to a servlet.
(edited post if you remove the space between & and amp you will get the correct character since in stackoverflow I couldn't find a way to do that I decided to put like that!)

Seems to be XML entity encoding, and a numeric character reference (decimal).
A numeric character reference refers to a character by its Universal
Character Set/Unicode code point, and uses the format
You can get some info here: List of XML and HTML character entity references on Wikipedia.
Your character is number 39, being the apostrophe: ', which can also be referenced with a character entity reference: '.
To decode this using Javascript, you could use for example php.js, which has an html_entity_decode() function (note that it depends on get_html_translation_table()).
UPDATE: in reply to your edit: Basically that is the same, the only difference is that it was encoded twice (possibly by mistake). & is the ampersand: &.

This is an SGML/HTML/XML numeric character entity reference.
In this case for an apostrophe '.

Store Html.Raw() in a string in Javascript, ASP.NET MVC 3

I'm using ASP.NET and I have a string of HTML in the database.
I want to get that html into a variable on the client.
If I do this:
var x = '#Html.Raw(myModel.FishValue)'
it works fine, because it's essentially doing
var x = '<p>hello!</p>';
however if there are quotes in the html it breaks the page.
My initial guess would be to .Replace the raw string to add escapes to the quotes, however both .ToString() and .ToHtmlString() (as Html.Raw returns an IHtmlString) do not produce the same markup as simple Html.Raw().
So I'm at a loss of what best to do.

What about replacing before calling the Html.Rawmethod?
var x = '#Html.Raw(myModel.FishValue.Replace("'","\\'"))'
UPDATE:
There might be other escape chars in the string coming from the model. For that reason I would recommend replacing the slashes first as well. Of course it all depends on what might come from the server in your model.
var x = '#Html.Raw(myModel.FishValue.Replace("\\","\\\\'").Replace("'","\\'"))'
A sample snippet representing the behavior in the javascript:
//Let's say my Model Content is > I'd Say \ is a escape character. You can't "Escape"
// YOu would have to replace ' --> \' and \ --> \\
var stringFromServer = 'I\'d Say \\ is a escape character. You can\'t "Escape"'
alert(stringFromServer)

Try this:
var x = '#(System.Web.HttpUtility.HtmlEncode(myModel.FishValue))';
If you need to decode the HTML on the client side use
unescape(x)
I think JQuery (not sure if you're using it or not) handles encoded HTML strings so you might not need unescape().

Try out the anti-xss library from Microsoft (which will be included I believe by default in asp.net 4.5):
AntiXss.JavascriptEncode(yourContent)
Anti-Xss is available 4.1 beta. If you want to use it in your application which I highly recommend, check out:
http://weblogs.asp.net/jgalloway/archive/2011/04/28/using-antixss-4-1-beta-as-the-default-encoder-in-asp-net.aspx

POST data issues

I have an issue with submitting post data. I have a form which have a couple of text fields in, and when a button is pressed to submit the data, it is run through a custom from validation (JS), then I construct a query string like
title=test&content=some content
which is then submitted to the server. The problem I had is when I have '&' (eg &nbsp) entered into one of the inputs which then breaks up the query string. Eg:
title=test&content=some content &nbsp
How do I get around this?
Thanks in advance,
Harry.

Run encodeURIComponent over each key and value.
var title = "test";
var content = "some content &nbsp ";
var data = encodeURIComponent('title') + /* You don't actually need to encode this as it is a string that only contains safe characters, but you would if you weren't sure about the data */
'=' + encodeURIComponent(title) +
'&' + encodeURIComponent('content') +
'=' + encodeURIComponent(content);

Encode the string..when you want to encode a query string with special characters you need to use encoding. ampersand is encoded like this
title=test&content=some content %26
basically any character in a query string can be replaced by its ASCII Hex equivalent with a % as the prefix
Space = %20
A = %41
B = %42
C = %43
...

You need to encode your query to make it URL-safe. You can refer to the following links on how to do that in JS:
http://xkr.us/articles/javascript/encode-compare/
http://www.webtoolkit.info/javascript-url-decode-encode.html

You said:
...and when a button is pressed to submit the data, it is run through a custom from validation (JS), then I construct a query string...
In the section where you are building the query string you should also run the value of each input through encodeURIComponent() as David Dorward suggested.
As you do - be careful that you only assign the new value to your processed query string and NOT the form element value, otherwise your users will think their input was somehow corrupted and potentially freak out.
[EDIT]
I just re-read your question and realized something important: you're encoding an &nbsp ;character. This is probably a more complicated issue than other posters here have read into. If you want that character, and other &code; type characters to transfer over you'll need to realize that they are codes. Those characters &, n, b, s, p and ; are not themselves the same as " " which is a space character that does not break.
You'll have to add another step of encoding/decoding. You can place this step either before of after the data is sent (or "POSTed").
Before:
(Using this question's answers)
var data = formElement.value;
data = rhtmlspecialchars(data, 0);
Which is intended to replace your "special" characters like with " " so that they are then properly encoded by encodeURIComponent(data)
Or after:
(using standard PHP functions)
<?PHP
$your_field_name = htmlspecialchars_decode(urldecode($_POST['your_field_name']));
?>
This assumes that you escaped the & in your POST with %26
If you replaced it with some function other than encodeURIComponent() you'll have to find a different way to decode it in PHP.

This should solve your problem:
encodeURIComponent(name)+'='+encodeURIComponent(value)+'&'+encodeURIComponent(name2)+'='+encodeURIComponent(value2)
You need to escape each value (and name if you want to be on the safe side) before concatenating them when you're building your query.
The JavaScript global function encodeURIComponent() does the escaping.
The global function escape() (DOM) does this for you in a browser. Although people are saying it is not doing the escaping well for unicode chars. Anyway if you're only concerned about '&' then this would solve your problem.

javascript escape problem with unicode characters

I use the following jquery code to load some date on a specific event from external file:
$("#container").load("/include/data.php?name=" + escape(name));
if the javascript "name" variable contains unicode characters it sends some encoded symbols to data.php file, something like this: %u10E1
How can I deal with this encoded symbols? I need to convert them back to readable one.
When I remove the escape function and leave just "name" variable the code doesn't work any more...
Can anyone please help?

If you want to do this manually, then you should be using encodeURIComponent, not escape (which is deprecated)
The jQuery way, however, would be:
$("#container").load("/include/data.php", { "name": name });
Either way PHP should decode it automatically when it populates $_GET.

This may help you.
javascript - how to convert unicode string to ascii