<style>
.a{font-size:12pt}
.b{font-size:20pt;color:blue}
</style>
<SCRIPT LANGUAGE="JavaScript">
function cg(index)
{
    var table = document.getElementById("table1");
    for (var i=0;i<table.rows.length;i++)
    {
        if(i==index)
            table.rows[i].className="b";
        else
            table.rows[i].className="a";
    }
}
</SCRIPT>

<TABLE border=1 width=200 id="table1" class="a">
<TR onclick="cg(this.rowIndex)">
    <TD>1</TD>
    <TD>1</TD>
    <TD>1</TD>
</TR>
<TR onclick="cg(this.rowIndex)">
    <TD>2</TD>
    <TD>2</TD>
    <TD>2</TD>
</TR>
<TR onclick="cg(this.rowIndex)">
    <TD>3</TD>
    <TD>3</TD>
    <TD>3</TD>
</TR>
</TABLE>