论hasLayout

1.Resetting hasLayout：

• width, height (to 'auto')
• max-width, max-height (to 'none') (in IE 7)
• position (to 'static')
• float (to 'none')
• overflow (to 'visible') (in IE 7)
• zoom (to 'normal')
• writing-mode (from 'tb-rl' to 'lr-tb')

2.css Properties hack

position: absolute

Refers to its containing block, and that's where some problems begin.

float: left|right

The float model has a lot of quirks due to some aspects of a layout element.

display: inline-block

Sometimes a cure when the element is at inline level and needs layout. Applying layout is probably the only real effect of this property. The “inline-block behaviour” itself can be achieved in IE, but quite independently: IE/Win: inline-block and hasLayout.

width: any value other than 'auto'

This is often an implicit fix, more often the trigger when hasLayout does things wrong.

height: any value other than 'auto'

height: 1% is used in the Holly Hack.

zoom: any value other than 'normal' (MSDN)

MS proprietary, does not validate. zoom: 1 can be used for debugging.

writing-mode: tb-rl (MSDN)

MS proprietary, does not validate.