I want to start, to dive more into web development. I used to be satisfied with an application that is simply working but now I want to focus a little bit on the ease of use and the design as well. I found a really cool website with a nice way to login. You do a javascript onclick (I guess) and then a little window pops up. I tried to figure out what it is and searched in the source code of [this site](http://www.aiga.org/) and I found following line where I still don't get how to do that. 

```
<input
    type="image" name="ctl00$Header1$LoginUserControl1$BtnLogin" id="ctl00_Header1_LoginUserControl1_BtnLogin"
    title="Login"
    src="/media/images/login_button.png"
    onclick="javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(&quot;ctl00$Header1$LoginUserControl1$BtnLogin&quot;, &quot;&quot;, false, &quot;&quot;, &quot;https://my.aiga.org/vango/core/login.aspx&quot;, false, false))" />

```

Does anyone have a guess how they designed that ?

**Edit**: I thank you very much for your answers. I really don't want to dive in into asp.net :/ Do you have any tutorials or suggestions on how to do that with javascript in some way ?