ZIndex and PNG

The z-axis is activated after the element is set position to absolute or relative, the size is set by the Z-index, the larger the Z-index, the higher the element position. If the Z-index value of multiple elements is the same, then the elements appearing in the HTML tag will float above the preceding element.

Multi-element position overlap, in addition to setting position to absolute or relative activation z-index, there is a special case that it does not activate Z-index, but still let the element position overlap-Negative margins

The same select element is displayed as a window under IE6, which is a bug in IE6. Using IFRAME to solve the display bug of select and floating elements under IE6

The PNG format is one of the most popular image formats in the Web because of its excellent compression algorithms and perfect support for transparency, but IE6 's transparent support for PNG is not good enough to solve this problem with the filter function under IE.

ZIndex and PNG