Which border-style property must be applied with border-width property?

Answer:

If we are setting control's border-width property value to any value in pixel then border-style solid,dashed,double or dotted must be applied alongwith border-width property values.

For Example:-

<asp:Button ID="Button4" runat="server" Text="Button" style="border-width:1px;border-style:solid;"/>     

<div style="border-width:2px;border-style:dotted;">Hello</div>