In the css, defined by line-height line-height attribute, (attribute value proportional value, proportional to the size and font, except directly define the height value attribute value).
But in fact, it may be subject to several other local effects:
First, font-family, high-different fonts default behavior is not the same;
Second, font-weight, bold, serif fonts and normal line height is not the same as a font may contain multiple fonts, font-style italic affect untested.
Third, the character set font-family font is not included in the font, such as special symbols ✆, normally does not contain this symbol font, different font setting has no effect on such symbols.