固定DataGrid表头

.fixHeaderStyle { FONT-SIZE: 9pt; VERTICAL-ALIGN: middle; TEXT-TRANSFORM: capitalize; FONT-FAMILY: "Arial" , "Helvetica" , "sans-serif"; POSITION: relative; ; TOP: expression(this.offsetParent.scrollTop<20 ? this.offsetParent.scrollTop:this.offsetParent.scrollTop-90 ); HEIGHT: 25px; BACKGROUND-COLOR: #ecf4fe; TEXT-ALIGN: center; TEXT-DECORATION: none }