is not a valid value for the 'left' property., Validation Error in CSS Options

[Joe_1975]

I'm using the following in my stylesheet.css file. I got the following errors which I marked in red. Please help why this error is showing

div#div-datagrid {
width: 220px;
height: 100px;
overflow: auto;
scrollbar-base-color:#ffeaff; ' Validation (CSS 2.1): 'scrollbar-base-color' is not a known CSS property name.
}

/* Locks the left column */
td.locked, th.locked {
font-size: 14px;
font-weight: bold;
text-align: center;
background-color: navy;
color: white;
border-right: 1px solid silver;
position:relative;
cursor: default;
/*IE5+ only*/
left: expression(document.getElementById("div-datagrid").scrollLeft-2); 'Validation (CSS 2.1): 'expression(document.getElementById("div-datagrid").scrollLeft-2)' is not a valid value for the 'left' property.
}

/* Locks table header */
th {
font-size: 14px;
font-weight: bold;
text-align: center;
background-color: navy;
color: white;
border-right: 1px solid silver;
position:relative;
cursor: default;
/*IE5+ only*/

left : expression(document.getElementById("div-datagrid").scrollLeft-2); 'Validation (CSS 2.1): 'expression(document.getElementById("div-datagrid").scrollLeft-2)' is not a valid value for the 'left' property.


top: expression(document.getElementById("div-datagrid").scrollTop-2); ' Validation (CSS 2.1): 'expression(document.getElementById("div-datagrid").scrollTop-2)' is not a valid value for the 'top' property.
z-index: 10;
}

/* Keeps the header as the top most item. Important for top left item*/
th.locked {z-index: 99;}

/* DataGrid Item and AlternatingItem Style*/
.GridRow {font-size: 10pt; color: black; font-family: Arial;
background-color:#ffffff; height:35px;}
.GridAltRow {font-size: 10pt; color: black; font-family: Arial;
background-color:#eeeeee; height:35px;}

[Christian J]

That's because they are proprietary MSIE extensions, and as such not part of the W3C spec.

If you want things to validate you might put them in a separate stylesheet, and hide that from the validator with MSIE's Conditional Comments.