Question

i need a regex in c# that will escape double quotes inside string literal. so if i have this string: “How about “this” and how about “that””. i will be able to use it in javascript without errors. because i am writing this literal to the page as js var.

EDIT: i will try to explain more about the problem.
i writing messege to the page like this:

string UserMsg = GetMessageText(999);
StringBuilder script = new StringBuilder();
script.AppendFormat("var UserMsg =\"{0}\";{1}", UserMsg, Environment.NewLine);
ScriptManager.RegisterClientScriptBlock(this, GetType(), "scriptparams", script.ToString(),true); 

now lets say messege 999 is this: “we found a “problem” in your details”.
this is causing js errors.

Answer 1

You should not use regular expressions to escape your C# strings into a JavaScript friendly / safe format. Instead, assuming you are using .NET 4, you can use HttpUtility.JavaScriptStringEncode and it’s overload to take care of both single and double quotes for you.

For example:

string UserMsg = GetMessageText(999);
StringBuilder script = new StringBuilder();
script.AppendFormat("var UserMsg =\"{0}\";{1}", HttpUtility.JavaScriptStringEncode(UserMsg), Environment.NewLine);
ScriptManager.RegisterClientScriptBlock(this, GetType(), "scriptparams", script.ToString(),true); 

Would ouput the following with UserMsgset to “we found a “problem” in your details”:

var UserMsg ="we found a \"problem\" in your details";