Form Validation

<script language="javascript" type="text/javascript">
function verify()
{
if (document.forms[0].elements[0].value=="")
{
  alert("Please Enter your Name");
  document.forms[0].elements[0].focus()
  return(false);
}

if (document.forms[0].elements[2].value=="")
{
  alert("Please Enter your City");
  document.forms[0].elements[2].focus()
  return(false);
}
if (document.forms[0].elements[4].value=="")
{
  alert("Please Enter your Country");
  document.forms[0].elements[4].focus()
  return(false);
}

if(document.forms[0].elements[5].value.indexOf(" ") >= 0)
{
 alert("Please enter your email-id without any white space character.");
  document.forms[0].elements[5].value="";
  document.forms[0].elements[5].select();
  document.forms[0].elements[5].focus();
 return (false);
}
if ( (document.forms[0].elements[5].value.indexOf("@") == -1) || (document.forms[0].elements[5].value.indexOf(".") == -1) )
{
 alert("Please enter a valid email-id");
  document.forms[0].elements[5].value="";
  document.forms[0].elements[5].select();
  document.forms[0].elements[5].focus();
 return (false);
}
BeforeAtRate = document.forms[0].elements[5].value.substring(0,document.forms[0].elements[5].value.indexOf("@"));
AfterAtRate = document.forms[0].elements[5].value.substring(document.forms[0].elements[5].value.indexOf("@")+1,document.forms[0].elements[5].value.length);
if (AfterAtRate.indexOf(".") == -1)
{
 alert("Please enter a valid email-id");
  document.forms[0].elements[5].value="";
  document.forms[0].elements[5].select();
  document.forms[0].elements[5].focus();
 return (false);
}
middle = AfterAtRate.substring(0, AfterAtRate.indexOf("."))
last = AfterAtRate.substring(AfterAtRate.indexOf(".") + 1,AfterAtRate.length)
if (BeforeAtRate.length == 0 || middle.length == 0 || last.length == 0)
{
 alert("Please enter a valid email-id");
  document.forms[0].elements[5].value="";
  document.forms[0].elements[5].select();
  document.forms[0].elements[5].focus();
 return (false);
}
if (document.forms[0].elements[6].value=="")
{
  alert("Please Enter your Phone Number");
  document.forms[0].elements[6].focus()
  return(false);
}
if(isNaN(document.forms[0].elements[6].value))
   {
     alert("Invalid data format.\n\nOnly numbers are allowed.");
     document.forms[0].elements[6].value="";
  document.forms[0].elements[6].select();
  document.forms[0].elements[6].focus();
     return (false);
   }
if (document.forms[0].elements[7].value=="")
{
  alert("Please Enter your Message");
  document.forms[0].elements[7].focus()
  return(false);
}
}
</script>