Get check Box value from Java Script function

i have some checkboxes as shown

 <td style="padding-left: 10px" width="70px">


                            <asp:CheckBox ID="ChkDytLek" runat="server" class="llogariDyt"
                                GroupName="Monedha" Text="Lek" CssClass="radioMarginLeft" OnClick="ChkValidate()"  />&nbsp;&nbsp; <img src="images/eagle-clipart-albanian-7.jpg" width="24px" height="15px"/>
                        </td>

                          <td >  


                                 <asp:CheckBox ID="ChkDytCAD" runat="server" 
                                GroupName="Monedha" Text="CAD" CssClass="radioMarginLeft" class="llogariDyt" OnClick="ChkValidate()" />&nbsp;&nbsp; <img src="images/CAD.png" width="24px" height="15px" />
                        </td>
                    </tr>
                    <tr>
                      <td>   </td>
                        <td style="padding-left: 10px">


                            <asp:CheckBox ID="ChkDytEU" runat="server"
                                GroupName="Monedha" Text="EUR" CssClass="radioMarginLeft" class="llogariDyt"  OnClick="ChkValidate()" />&nbsp;&nbsp; <img src="images/eu.png"width="24px" height="15px" />
                        </td>

but i want to limit the user to select not more than 2 of them. I am using a java Script function, but i cant tell why the function is called but enters only in alert(1) and doesn't get the values of my check boxes. I am calling them the wrong way or something?

function ChkValidate() {

              var NewCount = 0

              if (document.getElementsByClassName("chkDytLek").checked = true)
              { NewCount = NewCount + 1 }
              alert(2);
              if (document.getElementById("chkDytUSD").checked = true)
              { NewCount = NewCount + 1 }
              alert(3);
              if (document.getElementById("chkDytEUR").checked = true)
              { NewCount = NewCount + 1 }

              if (document.getElementById("chkDytCAD").checked = true)
              { NewCount = NewCount + 1 }

              if (document.getElementById("chkDytCHF").checked = true)
              { NewCount = NewCount + 1 }

              if (NewCount == 3) {
                  alert('Pick Just Two Please')
                  document.forms; return false;
              }
          }