How do I convert escape characters in Javascript to a .txt file?

Question

I have an HTML file that is using Javascript to do file I/O operations on a .txt file, via an ActiveXObject (only works in Internet Explorer, on Windows OS).

There is a text input box on the HTML page, and a button. The button calls a function onclick to write the text entered to the end of the .txt file. There is also a textarea on the HTML page, in which the modified contents of the .txt file are copied and pasted into. All of this is working so far...

So, I want to insert tabs and new-lines into the .txt file, from my HTML page with Javascript. I am using this line to copy the .txt file contents into the textarea, initialized in a variable:

var newText = oldText + "\n" + document.getElementById("userInput").value;

Of course, the escape character \n works on the HTML page, and not in the .txt file...

So how do I encode new lines, and tabs as well, into a parsable format for the .txt file? I have tried using the escape() method on ANSI values found here, and on ASCII values found here, but with no luck.

Here is my code so far:

<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title>New Web Project</title>
    </head>
    <body>

        <p>
            Enter some text here: &nbsp;
            <input type = "text" id = "userInput" />
        </p>

        <input type = "button" value = "submit" onclick = "main();" />
        <br />
        <hr />
        <br /><br /><br />
        <textarea id = "textHere" rows = 25 cols = 150></textarea>

        <script type = "text/javascript">

            // executes all code from this function to prevent global variables
            function main()
            {
                var filePath = getThisFilePath();

                var fileText = readFile(filePath);
                writeFile(filePath, fileText);

            } // end of function main

            function getThisFilePath()
            {
                var path = document.location.pathname;

                // getting rid of the first forward-slash, and ending at the last forward-slash to get rid of file-name
                var correctPath = path.substr(1, path.lastIndexOf("/") );

                var fixedPath = correctPath.replace(/%20/gi, " "); // replacing all space entities

                return fixedPath;
            } // end of function getThisFilePath

            function readFile(folder)
            {
                var fso = "";
                var ots = "";
                var oldText = "";

                try
                {
                    fso = new ActiveXObject("Scripting.FileSystemObject");

                    // in the same folder as this HTML file, in "read" mode (1)
                    ots = fso.OpenTextFile(folder + "writeToText.txt", 1, true);

                    oldText = ots.ReadAll();

                    ots = null;
                    fso = null;
                }
                catch(e)
                {
                    alert("There is an error in this code!\n\tError:  " + e.message);
                    exit(); // end the program if there is an error
                }

                return oldText;

            } // end of function readFile

            function writeFile(folder, oldText)
            {
                var fso = "";
                var ots = "";

                var newText = oldText + "\n" + document.getElementById("userInput").value;

                try
                {
                    fso = new ActiveXObject("Scripting.FileSystemObject");

                    // in the same folder as this HTML file, in "write" mode (2)
                    ots = fso.OpenTextFile(folder + "writeToText.txt", 2, true);

                    ots.Write(newText);
                    ots.Close();

                    ots = null;
                    fso = null;
                }
                catch(e)
                {
                    alert("There is an error in this code!\n\tError:  " + e.message);
                    exit(); // end the program if there is an error
                }

                setText(newText); // with the function below

            } // end of function writeFile

                // called from the function writeFile
                function setText(textFile)
                {
                    document.getElementById("textHere").value = textFile;

                } // end of function setText

        </script> <!-- end of javascript -->
    </body>
</html>

Ah, I didn't know about that! Ha, that's a lot easier than what I was trying to do. Yes, `\r\n` works, as well as any additional escape sequences after `\r` as well, such as: `\r\n\t\t`. Thanks for the help @Bergi, answer the question and I will mark it as best. ;) — Ian Campbell, Jul 27 '12 at 19:45

score 2 · Accepted Answer · answered Jul 27 '12 at 19:53

2

Windows expects "\r\n" as linebreaks. I'm quite sure you would find them in your textarea's value as well (after hitting enter). They will get automatically inserted when you set a value with "\n", and most libraries (like jQuery) do replace them with "normal" linebreaks when reading the value.

However, I would expect a file read/write with only "\n" to work, and when you load the file's text into your textarea they should show up. MS Notepad might have problems showing them.

answered Jul 27 '12 at 19:53

Bergi

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Ah, exactly -- there is a need to use my text file with Notepad, so I have been testing it with that... which as you are saying has problems with `\n` *without* the windows line-break "`\r\n`". Thanks for the help Bergi. – Ian Campbell Jul 27 '12 at 21:21
Use Notepad++ (free), there you can set and change linebreaks :-) – Bergi Jul 27 '12 at 21:29

How do I convert escape characters in Javascript to a .txt file?

1 Answers1