Comments within style= attributes - safe?

Question

I am working on a CMS that generates CSS "style='xyz'" statements from user input. The user input will be validated but as an additional safeguard, I want to check the validity of the values on generation of the CSS code.

If an invalid value is encountered - e.g. a relative width ("50%") where only absolute values are allowed due to layout restrictions - I would like to return a comment INSIDE the style attribute to help debugging:

<div class="content" style="background-color: lightblue; /* WIDTH was invalid: Only absolute values allowed here */; border: 1px orange dotted;">

Is this "safe", i.e. will all major browsers still parse the settings before and after the comment properly? It is difficult to Google information about this.

Answer 1

It is probably safe but I wouldn't put the wrong values commented into the markup.

Let the user know they did something wrong in the very beginning before you generate markup.

A good idea would be to create such a test case and feed it to the W3C validator to see what it would say says about it.

http://validator.w3.org/

Answer 2

From the top of my head, IE supports it, Fx doesn't.