var al1 = $F("txtSDate").split('-');
    var al2 = $F("txtEDate").split('-');
    
    
    var sd = new Date(al1[0],parseInt(al1[1]-1),al1[2]);
    var ed = new Date(al2[0],parseInt(al2[1]-1),al2[2]);
    
    if(sd > ed)
    {
        alert("有效结束日期要大于开始日期！");
        $("txtSDate").focus();
        return false;
    }