fixing gridview header while scrolling

问题:

I had fixed GridView header and while i scroll down headers will be constant but the problem is headers are not in proper format. Like all the column headers are shrinked and wont display under particular column . I tried many things but nothing was useful. Clearly saing header width is not equal to column. I have used JavaScript code for Scrolling and also CssClass for Fixing.

Please find the solution for me

JavaScript Code

 <script type = "text/javascript">
        var GridId = "<%=GridViewLeaveHistory.ClientID %>";
        var ScrollHeight = 300;
        var ScrollWidth = 300;
        window.onload = function () {
            var grid = document.getElementById(GridId);
            var gridWidth = grid.offsetWidth;
            var gridHeight = grid.offsetHeight;
            var headerCellWidths = new Array();
            for (var i = 0; i < grid.getElementsByTagName("TH").length; i++) {
                headerCellWidths[i] = grid.getElementsByTagName("TH")[i].offsetWidth;
            }
            grid.parentNode.appendChild(document.createElement("div"));
            var parentDiv = grid.parentNode;

            var table = document.createElement("table");
            for (i = 0; i < grid.attributes.length; i++) {
                if (grid.attributes[i].specified && grid.attributes[i].name != "id") {
                    table.setAttribute(grid.attributes[i].name, grid.attributes[i].value);
                }
            }
            table.style.cssText = grid.style.cssText;
            table.style.width = gridWidth + "px";
            table.appendChild(document.createElement("tbody"));
            table.getElementsByTagName("tbody")[0].appendChild(grid.getElementsByTagName("TR")[0]);
            var cells = table.getElementsByTagName("TH");

            var gridRow = grid.getElementsByTagName("TR")[0];
            for (var i = 0; i < cells.length; i++) {
                var width;
                if (headerCellWidths[i] > gridRow.getElementsByTagName("TD")[i].offsetWidth) {
                    width = headerCellWidths[i];
                }
                else {
                    width = gridRow.getElementsByTagName("TD")[i].offsetWidth;
                }
                cells[i].style.width = parseInt(width - 3) + "px";
                gridRow.getElementsByTagName("TD")[i].style.width = parseInt(width - 3) + "px";
            }
            parentDiv.removeChild(grid);

            var dummyHeader = document.createElement("div");
            dummyHeader.appendChild(table);
            parentDiv.appendChild(dummyHeader);
            var scrollableDiv = document.createElement("div");
            if (parseInt(gridHeight) > ScrollHeight) {
                gridWidth = parseInt(gridWidth) + 17;
            }
            scrollableDiv.style.cssText = "overflow:auto;height:" + ScrollHeight + "px;width:" + gridWidth + "px" + ScrollWidth;
            scrollableDiv.appendChild(grid);
            parentDiv.appendChild(scrollableDiv);
        }

Css Class

.Freezing 
    { 
    position: relative;  
    top: expression(this.offsetParent.scrollTop-1); 
    z-index: 10; 
    }

GridView Code

<div style="width: 810px; height: 259px;">
 <asp:GridView ID="GridViewLeaveHistory" runat="server" AllowSorting="True" 
  AutoGenerateColumns="False" BackColor="White" BorderColor="#0061C1" 
  BorderStyle="None" CaptionAlign="Bottom" EmptyDataText="No Records Found" 
  Font-Names="Verdana" Font-Size="X-Small" ForeColor="#0061C1" Height="18px" 
  OnRowCommand="GridViewLeaveHistory_RowCommand" 
  OnRowDataBound="GridViewLeaveHistory_RowDataBound" CssClass="Freezing"                                                       
  OnSelectedIndexChanged="GridViewLeaveHistory_SelectedIndexChanged"                                                      
  ShowFooter="True" ShowHeaderWhenEmpty="True" width="801px">