1.Transparency
Writing

1.1 mainstream browser writing

div{background-color:rgba(255,255,255,0.8);}/*forIE10+,firefox,chrome*/

1.2 for IE 9-browser

div{filter:progid:DXImageTransform.Microsoft.Gradient(GradientType=0,StartColorStr="#ccffffff",EndColorStr="#ccffffff");/*IE6-9*/}

2. grammar intensive lectures

2.1filter:progid:DXImageTransform.Microsoft.Gradient( )

filter:progid:DXImageTransform.Microsoft.Gradient(
GradientType=0,/*GradientType:Read and writeable. Integer value (Integer). Set or retrieve the direction of the color gradient. 1|0*/
StartColorStr="#ccffffff",/*Optional. String(String). Set or retrieve the start color and transparency of the color gradient. */
EndColorStr="#ccffffff" /* optional. String(String). Set or retrieve the end color and transparency of the color gradient. */
)

/*
*@StartColorStr,EndColorStr: its format is #AARRGGBB.
*AA, RR, GG, BB are hexadecimal positive integers. The range of values is 00-FF.
*RR specifies the red value, GG specifies the green value, BB specifies the blue value, and AA specifies the transparency (00 is completely transparent, FF is completely opaque). Values out of the range will be restored to the default value.
* StartColorStr, default value is #FF0000FF, opaque blue, EndColorStr, default value is #FF000000, opaque black.
*/