Develop Reference

js_string with double quoted expression

We have a FTL that has -
<a href='javascript:func("${event.title}");'>Link</a>
When the value has an apostrophe, like Norman'S Birthday - it breaks.
We used js_string to fix it -
Link
But we also had to change the double quotes around $expression to single quotes - this does Not work with double quotes.
Question -
Is there a way to fix this with the original double quotes around the $expression ?
Something like -
<a href='javascript:func("${event.title?js_string}");'>Link</a>
Note the above does not work.

You need two kind of escaping applied here: JavaScript string escaping and HTML escaping. You need both, as the two formats are independent, and the JavaScript is embedded into HTML.
How to do that... the primitive way is event.title?js_string?html, but it's easy to forget to add that ?html, so don't do that. Instead, use auto-escaping (see https://freemarker.apache.org/docs/dgui_quickstart_template.html#dgui_quickstart_template_autoescaping). If you can't use that form of auto-escaping for some reason (like you are using some old FreeMarker version and aren't allowed to upgrade), put the whole template into <#escape x as x?html>...</#escape>. In both cases, you can just write ${event.title?js_string}, and it will just work.
However, if you are using #escape, ensure that the incompatible_improvements setting (see https://freemarker.apache.org/docs/pgui_config_incompatible_improvements.html) is at least 2.3.20, or else ?html doesn't escape '.

Modify the value of event.title so that single quotes are replaces with ' and double quotes are replaces with ", then you won't have to worry at all about which kind of quotes you use for the rest of it.

?js_string should be outside curly brackets {}. Now you should use double quotes " " around href value, if you wanna handle single quotes ' ' inside the string and vice versa. Single and double quote can not be used in same string, so either of them needs to be replaced to other.
solution:
Link
Same expression can be used in JavaScript to handle special characters

Single quote JSP to JavaScript function

I have a string that must be used to be passed into a JavaScript function. I have tried many ways, but I still cannot make it to work.
<%=name%>
The name field is a string that contains single quotes such as It's Morning. I have tried to use:
String nameString = rs.getString("name");
nameString = nameString.replaceAll("'","\'");
<%=nameString%>
And also
nameString = URLEncoder.encode(nameString);
And also
nameString = nameString.replaceAll("'","'");
And also
nameString = nameString.replaceAll("'","&apos;");
I still cannot get it to work. And also I can't go for EL.

If you want to replace a single quote (') in a String with a JavaScript-escaped (backslashed) single quote (\') in Java code then you need to escape the backslash character (with a backslash!). For example:
nameString = nameString.replaceAll("'","\\'");
See also: String.replaceAll single backslashes with double backslashes

Try to use String.fromCharCode(39) instead of single quote, String.fromCharCode(39) is ASCII codes for single quote.

If you are doing it inside JSP tag, you need to have sufficient backslashes for one of them to actually make it into the web page. The code would be:
<%=nameString%>
You need one backslash to escape the other backslash and each of those needs to be escaped - hence four backslashes (yuck).
Hope that helps.

The following worked for me, as the HTML encoding is done before the function call and replaced the single quote with '.
nameString = nameString.replaceAll("'","\\'");

How to deal with sigle quote in javascript in jsp page?

onclick= "_deleteWPSchemeData(${viewWPMasterGrid.id}, '${viewWPMasterGrid.name}')"
${viewWPMasterGrid.name} retutrns me a string(for e.g. W.P.WINT OFF ALL'10) which often has single quote character so from the calling javascript method I am not getting the second parameter at all. How to deal with problem?

When a dynamic String can be put inside a JavaScript string literal, it should be JS-escaped. Just as when a dynamic String is put inside a HTML page, it's HTML-escaped.
Use commons-lang StringEscapeUtils.escapeECMAScript (or escapeJavaScript depending on the version) to escape the String. You could create a very simple EL function to do that straight from the JSP.
Note that you could have problems with single quotes, but also double quotes, tags, EOLs, backslash, which must all be escaped in a JS String literal.

It looks like you could split the second parameter out into its own variable first. If I have understood your question correctly.
var viewWPMasterGridName = "${viewWPMasterGrid.name}";
onclick = "_deleteWPSchemeData(${viewWPMasterGrid.id},'" + viewWPMasterGridName + "')";

Use '${viewWPMasterGrid.name.replaceAll("'", "\'")}'

try this,
var name = "${viewWPMasterGrid.name}".replace(/'/g,"\\'");

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.

Using JavaScript single and double quotes for href's

I am having problem with escaping the single and double quotes inside the hrefs JavaScript function.
I have this JavaScript code inside href. It's like -
click this
Now, since double quotes inside double quote is not valid, I need to escape the inner double quotes for it to be treated as part of the string -
so, I need to do this -
click this
The problem is, even the above code is not working. The JavaScript code is getting truncated at -- myFunc(
I tried with the single quote variation too - but even that doesn't seem to work (meaning that if I have a single quote inside my string literal then the code gets truncated).
This is what I did with a single quote:
<a href = 'javascript:myFunc("fileDir/fileName.doc" , true)'> click this </a>
This works, but if I have a single quote inside the string then the code gets truncated in the same way as that of double quotes one.

Using backslashes to escape quotes is how it works in JavaScript, but you're not actually writing JavaScript code there: you're writing HTML. You can do it by using the HTML escaping method: character entities.
" // "
' // '
For example:
...

In case anyone needs to escape some thing like this:
<a href="www.google.com/search?q="how+to+escape+quotes+in+href""</a>
You can use ASCII code for double quotes %22:
<a href="www.google.com/search?q=%22how+to+escape+quotes+in+href%22"</a>
It is especially useful if you pass the link to JavaScript from PHP

As a general best practice, use double-quotes in HTML and single-quotes in JavaScript. That will solve most of your problems. If you need a single-quote in a JavaScript string, you can just escape it using \' - and you probably shouldn't be nesting literal strings any deeper than that.
As noted elsewhere, HTML entities are a possibility if the code is embedded in HTML. But you'll still have to deal with escaping quotes in strings in your JavaScript source files, so it's best to just have a consistent strategy for dealing with JavaScript.
If you are following this strategy and end up with a double-quote embedded in your JavaScript embedded in your HTML, just use the HTML entity ".

Normally, this kind of code is working without problems:
Click this
With this code, do you have any problem?