Howto display non-printable characters in html webpages

Question

I have a collection of webpage scripts that take FIX message data as input and then reformat and analyse them. Under IE7 (and IE8, and older Firefoxes too I think), these tools could print a FIX message to a webpage, and the non-printable characters (eg. 0x01 delimiters) would show as an empty box symbol / glyph.

Under IE9, and Firefox 25, this doesn't happen any more. The 0x01 bytes are printed to screen and are "visually truncated", even though they are still there on the page. e.g. I can copy the FIX message text and paste it into notepad++ I have verified that the 0x01 bytes are definitely still there. The issue is that on the webpage the 0x01 bytes are not visible.

Try it. Copy and paste the below text into Notepad++ or another text editor and turn on "reveal special characters" and you should see the 0x01 delimiter characters, but they don't display below. For some reason, Stackoverflow is stripping the SOH characaters out of the string below unfortunately.

8=FIX.4.09=012235=U

1. Are there any new html tags that I can wrap the FIX messages in so that they will still print the box characters to screen for characters that are non-printable?

2. Is there any other workaround that would achieve this? I can substitute the 0x01 characters for eg. the "|" character, but I'd greatly prefer if there is a specific html tag or font that can make these non-printable characters visible, so that the FIX message itself is left intact.

Thanks in advance.

EDIT1. I have just tried using http://www.typetester.org/ and have checked 90% of available fonts and haven't found any that show a box symbol for 0x01 under firefox... :(

EDIT2. Just tried typetester.org using IE9 with the FIX message text and had the same results... no visible character of any kind with any fonts tried, yet the text displayed on the webpage and copied and pasted into notepad++ does show teh 0x01 characters are still there. Looks like doing this via a font may not be possible... Does anyone know of any particular tags that when wrapped around some text might change the display behaviour?

Answer 1

In the end, I ended up using a solution to substitute the characters into spaces... Far from what I was hoping - but at least it makes the tags readable again, instead of running together.

8=FIX.4.0 9=0122 35=U