Server Side validations firing in one machine and not in another - asp.net

Question

I have a page with 2 textbox control for account number and house number. Both the controls have required feild validators as well as regular expression. I have some server side validations too, that fires, only if the client side validations are passed.
The Problem is that, in my local dev VM, if I leave the textboxes blank and click the button, the client side validations fire. The same code is deployed to our Testing enviornment and on the testing site if I click the button leaving the textboxes as empty, both the server side as well as client side validations are fired.
I want the same behavior in testing enviornment also. i.e server side should fire only when client side validations are passed.
What is causing this behavior? I am little newbie to .net so excuse me if I am missing on some very fundamental concept here. The .net Version is 4.5 with Visual studio 2012
Code Account number:
<div id="textboxAccNumCss" runat="server">
<div class="form-group">
<asp:Label ID="lblAccontNumber" runat="server" Text="* Account Number"></asp:Label>
<asp:TextBox ID="txtAccountNumber" runat="server" class="form-control"></asp:TextBox>
</div>
<div>
<asp:RequiredFieldValidator ID="rfvAccountNumber" runat="server" ForeColor="Red" ValidationGroup="AccountValidation" ControlToValidate="txtAccountNumber" ErrorMessage="Enter Account Number"></asp:RequiredFieldValidator>
<asp:RegularExpressionValidator ID="rgxAccountNumber" runat="server" ControlToValidate="txtAccountNumber" ErrorMessage="Enter in Correct Format" ForeColor="Red" ValidationGroup="AccountValidation" ValidationExpression="\d{1,12}(-\d{1})?"></asp:RegularExpressionValidator>
</div>
</div>
Code for House Number
<div id="textboxHSnoCss" runat="server">
<div class="form-group">
<asp:Label ID="lblHouseNumber" runat="server" Text="*House Number"></asp:Label>
<asp:TextBox ID="txtHouseNumber" runat="server" class="form-control"></asp:TextBox>
</div>
<div>
<asp:RequiredFieldValidator ID="rfvHouseNo" ForeColor="Red" runat="server" ValidationGroup="AccountValidation" ControlToValidate="txtHouseNumber" ErrorMessage="Enter House Number"></asp:RequiredFieldValidator>
<asp:RegularExpressionValidator ID="rgxHouseNo" runat="server" ValidationGroup="AccountValidation" ControlToValidate="txtHouseNumber" ForeColor="Red" ErrorMessage="Enter in Correct Format" ValidationExpression="^[a-zA-Z0-9 #-/*]*$"></asp:RegularExpressionValidator>
</div>
</div>
Code for Button Click
<asp:Button ID="Button1" runat="server" Text="Continue" ValidationGroup="AccountValidation" OnClick="btnContinue_Click" class="btn btn-primary" />

Answer 1

Your first task should to make sure that client side validation is done successfully and then go for postback and server side validation. You could use the below js code to verify if the page is validated properly or not.
if (typeof (Page_Validators) != "undefined") {
if (typeof (Page_ClientValidate) == 'function') {
isPageValid = Page_ClientValidate("AccountValidation");
}
}
Based on the isPageValid value you could do stop or continue postback.