function chkform()

{



 <!--- Pflichteingaben prŸfen --->

 if(document.forms[0].vorname.value == "")

  {

   alert("Please enter your first name");

   document.forms[0].vorname.focus();

   return false;

  }

  

  if(document.forms[0].nachname.value == "")

  {

   alert("Please enter your second name");

   document.forms[0].nachname.focus();

   return false;

  }


  if(document.forms[0].firma.value == "")

  {

   alert("Please enter your Company");

   document.forms[0].firma.focus();

   return false;

  }
  

    if(document.forms[0].email.value == "")

  {

   alert("Please enter your email");

   document.forms[0].email.focus();

   return false;

  }

  

  <!--- Emailadresse validieren --->

 if (document.forms[0].email.value != "")

 	{

	var emailStr = document.forms[0].email.value

	var emailPat=/^(.+)@(.+)$/

	var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"

	var validChars="\[^\\s" + specialChars + "\]"

	var quotedUser="(\"[^\"]*\")"

	var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/

	var atom=validChars + '+'

	var word="(" + atom + "|" + quotedUser + ")"

	var userPat=new RegExp("^" + word + "(\\." + word + ")*$")

	var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")

	var matchArray=emailStr.match(emailPat)

	if (matchArray==null) {

  		alert("Your email is not correct")

		document.forms[0].email.focus();

   		document.forms[0].email.select();

		return false

	}

	

	var user=matchArray[1]

	var domain=matchArray[2]

 	if (user.match(userPat)==null) {

    	alert("Your email is not correct")

		document.forms[0].email.focus();

   		document.forms[0].email.select();

    	return false

	}

	

	var IPArray=domain.match(ipDomainPat)

	if (IPArray!=null) {

    	for (var i=1;i<=4;i++) {

	    	if (IPArray[i]>255) {

	        	alert("Your email is not correct")

				document.forms[0].email.focus();

   				document.forms[0].email.select();

			return false

	    	}

    	}

    	return true

	}



	var domainArray=domain.match(domainPat)

	if (domainArray==null) {

		alert("Your email is not correct")

		document.forms[0].email.focus();

   		document.forms[0].email.select();

    	return false

	}



	var atomPat=new RegExp(atom,"g")

	var domArr=domain.match(atomPat)

	var len=domArr.length

	if (domArr[domArr.length-1].length<2 || 

    	domArr[domArr.length-1].length>3) {

   		alert("Your email is not correct")

		document.forms[0].email.focus();

   		document.forms[0].email.select();

   	return false

	}



	if (len<2) {

		var errStr="Your email is not correct"

		alert(errStr)

		document.forms[0].email.focus();

   		document.forms[0].email.select();

   	return false

	}

  

return true;

}



return true;

}