Question

i tested ,when running on chrome or firefox, except on ie,
the position:fixed will trigger the display:block?
this the test html :http://sking7.github.com/fix.html
the code will alert two times,the first is display ,the second is document.compatMode
this why?
the w3c has said this ?

Answer 1

Well, I found the w3 specifications for this :

9.7 Relationships between ‘display’, ‘position’, and ‘float’

The three properties that affect box generation and layout — ‘display’, ‘position’, and ‘float’ — interact as follows:

1. If ‘display’ has the value ‘none’, then ‘position’ and ‘float’ do not apply. In this case, the element generates no box.
2. Otherwise, if ‘position’ has the value ‘absolute’ or ‘fixed’, the box is absolutely positioned, the computed value of ‘float’ is ‘none’, and display is set according to the table below. The position of the box will be determined by the ‘top’, ‘right’, ‘bottom’ and ‘left’ properties and the box’s containing block.
3. Otherwise, if ‘float’ has a value other than ‘none’, the box is floated and ‘display’ is set according to the table below.
4. Otherwise, if the element is the root element, ‘display’ is set according to the table below, except that it is undefined in CSS 2.1 whether a specified value of ‘list-item’ becomes a computed value of ‘block’ or ‘list-item’.
5. Otherwise, the remaining ‘display’ property values apply as specified.

Specified value                                     Computed value

inline-table                                        table

*inline*, table-row-group, table-column, 
table-column-group, table-header-group, 
table-footer-group, table-row, table-cell, 
table-caption, inline-block                         *block*

others                                              same as specified