Question

While viewing the source of a web page, I came across this CSS, applied to a span within a button:

.whatever button span {
    position: absolute;
    left: -1e+7px;
}

What does left: -1e+7px; mean? Is this some trick I should be aware of?

Answer 1

It appears to be scientific notation (in this case, for -10,000,000px). To the best of my knowledge, CSS does not allow scientific notation (it is absent from the standard, but a Google search for “css scientific notation” turns up several complaints against Batik — an SVG engine — for not supporting it). I would guess that some CSS parsers do support such notation, despite it not being part of the standard, but if so, I cannot find information on which parsers support it.

To be safe, I would avoid using it in your own stylesheets.