Assuming you mean "html and css" when you say "code line", I can only say that both Firefox and Chrome are open source, so just download that to study the details of there engines.
If you us the url and whatever more we need to reproduce the error on IE that isn't an error on Firefox somebody might be able to tell you the cause. But at the moment you don't provide enough info for that.
Kees
I asking about background differences (how a code line is interpretated, why os IE I get an error and on Firefox it don`t reproduced), not speed differences, on Mozilla Firefox, Google Chrome and Internet Explorer.

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