How to click/select Row in ASP.NET GridView or HTML Table

The above code will slow down the browser and the browser can hang when Rows in Grid will be 10000 or above. Please view the below suggestion:

CS Code

protected void grvGroups_RowDataBound(object sender, GridViewRowEventArgs e)
{
 if (e.Row.RowType == DataControlRowType.DataRow)
  {
    e.Row.Attributes.Add("onclick", "setGridValue('" + e.Row.ClientID + "')");
  }
}

HTML Code

.sel
{
     color: #303030;
     font-size:3em;
     font-weight:bold;
     cursor:default;
}
.desel
{
     color: #909090;
     font-size:2em;
     font-weight:normal;
     cursor:pointer;
}

var oldro;
function setGridValue(ro)
{
 var rs=document.getElementById(ro);
 if(oldro!=null)
 {
  if(rs.className=="sel")
   return;
  oldro.className="desel";
 }
 rs.className="sel";
 oldro=rs;
}

And forget then loop.