Confirm Box cancel button not working

/**********code for validation*******/

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

    if(document.form1.Userid.value=="")
    {
      alert("User Name should not be left blank");
      document.form1.Userid.focus();
      return false;
    }
   if(document.form1.Usertype.value=="")
    {
      alert("Usertype should not be left blank");
      document.form1.Usertype.focus();
      return false;
    }
     if(document.form1.Username.value=="")
    {
      alert("Username should not be left blank");
      document.form1.Username.focus();
      return false;
    }

     if(document.form1.Email.value=="")
    {
      alert("email should not be left blank");
      document.form1.Email.focus();
      return false;
    }
     if(document.form1.mobile.value=="")
    {
      alert("mobile should not  be left blank");
      document.form1.mobile.focus();
      return false;
    }
  
   var x=document.forms["form1"]["Email"].value
var atpos=x.indexOf("@");
var dotpos=x.lastIndexOf(".");
if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length)
  {
 
  alert("Not a valid e-mail address");
  return false;
  }
  
  
  ConfirmAmount();
   return true;
  
}

 </script>  
/**********End of validation*********/


/****Second function for confirm box******/
<script type="text/javascript"> 
function ConfirmAmount()
{
var amount = document.getElementById("Userid").value;
if(confirm("Confirm . Click OK if **" + amount + " is the correct Data."))


if (amount== true)
{
 document.form1.submit()
}
else
{
location.href="CreateUser.jsp";
}
}
  
 </script>

/************************************/

Step3:
/************Form**********/

       			 <form name="form1" method=post action="nuser.jsp" onsubmit="return validateForm()";>
 				   <label for="nuserid">Userid</label>
                   <input type="text" name="Userid" id="Userid" size="30"/><br/>
				   <div style="float:left; margin-5:px;"> <label for="nuserid">UserType</label><select name="Usertype" size="1">
					<option value="1" >VMR admin</option>
					<option value="2">MerchantCard</option>
					<option value="3">VMR Cust Support</option>
					<option value="4">CardHolder</option>
        			</select><br /></div>
                    <br/>
                     <label for="nuserid">UserName</label>
                   <input type="text" name="Username" id="Username" size="30"/><br/>
                   <label for="nuserid">Email</label>
                   <input type="text" name="Email" id="Email" size="30"/><br/>
                   <label for="nuserid">Mobile</label>
    	           <input type="text" name="mobile" id="mobile" size="20" maxlength="10" id="txtChar" onkeypress="return isNumberKey(event)" type="text" name="txtChar"/><br/>
	           
        		   <label for="nuserid">EffectiveDate</label><input type="text" name="start_date" value=""><div style="float:left; margin-5:px;">
           			<a href="javascript:showCalendar('',document.forms[0].start_date,null,'','',0,30,1)"><img src="images/Calendar_scheduleHS.png" width="16" height="16" alt="" border="0" /></a></div>

           
        <br/>
             <label for="nuserid">InactiveDate</label><input type="text" name="end_date" value=""/><div style="float:left; margin-5:px;"><a
  href="javascript:showCalendar('', document.forms[0].end_date, document.forms[0].start_date, '','', 0,30, 1)"><img src="images/Calendar_scheduleHS.png" width="16" height="16" alt="" border="0" /></a></div>

             <br/> 

              <div style="padding-left:300px"><input type="submit" value="ok"/></div>
            <input type="button" value="Back" onclick="goBack()"/>
                   </div> 
                  </form>  
                   <br/>
             
 </center>
/******End of Form*********/
                              

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