Validation Web form Using JAVASCRIPT

<script type="text/javascript">
        function Getname() {

            var param = document.getElementById('<%=DropDownList1.ClientID%>').value;
            var param1 = document.getElementById('<%=TextBox1.ClientID%>').value;
            var param2 = document.getElementById('<%=TextBox3.ClientID  %>').value;
            var param3 = document.getElementById('<%= TextBox4.ClientID %>').value;
            var param4 = document.getElementById('<%= TextBox5.ClientID %>').value;
            var param5 = document.getElementById('<%=TextBox6.ClientID%>').value;
            var param6 = document.getElementById('<%=TextBox7.ClientID%>').value;
            var param7 = document.getElementById('<%=DropDownList2.ClientID%>').value;
            if (param == '') {
                alert("Please select Category");
                return false;
            }
            if (param1 == '') {
                alert("Please enter Ad name");
                return false;
            }
            if (param2 == '') {
                alert("Please enter Description");
                return false;
            }
            if (param3 == '') {
                alert("Please enter  Price");
                return false;
            }
            if (param4 == '') {
                alert("Please enter Contact name");
                return false;
            }
            if (param5 == '') {
                alert("Please enter Email address");
                return false;
            }
            if (param6 == '' ) {
                alert("Please enter Phone no.");
                return false;
            }
            if (param7 == '') {
                alert("Please select City");
                return false;
            }
        }
</script>