How to prevent CSS declaration dropped errors cross browser?

Hi I would like to know how to easily prevent dropped errors from appearing from debugging software such as webdeveloper plugin in Firefox. I get errors such as:

Warning: Error in parsing value for 'filter'. Declaration dropped.

Warning: Error in parsing value for 'font'. Declaration dropped.

I understand I get these errors because Firefox does not support these CSS properties, but how do I drop them before hand so Firefox does not attempt to read them in the first place? I know I 开发者_Go百科can create a separate style sheet for every browser but that is a inconvenience. Is there a simple solution?

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1. I'd always put or import IE-specific styles inside a conditonal comment;

2. as standard CSS FF should be fine with 'font', so just check your syntax e.g. font: bold 12px/30px Georgia, serif; values separated by spaces, multi-word font names in quotes, etc.

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If you are using an IE-specific declaration (like filter), put it in an IE-specific stylesheet. It is simple and easy, and I don't really understand why it would be an incovenience (the inconvenience is IE itself).

Hiding an error does not mean the error is solved (and actually if FF shows an error in font it should be taken care of).