// JavaScript Document
// swap image when mouse over
function switchImage(imgName, imgSrc) 
{
  if (document.images)
  {
    if (imgSrc != "none")
    {
      document.images[imgName].src = imgSrc;
    }
  }
}

function emailCheck (emailStr) 
{
	//var emailStr=ofield.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 +")*$")
	
	// Begin with the coarse pattern to simply break up user@domain into different pieces that are easy to analyze.
	var matchArray=emailStr.match(emailPat)
	if (matchArray==null) {
	  // Too many/few @'s or something; basically, this address doesn't even fit the general mould of a valid e-mail address.
		alert("The Email address seems incorrect (check for @ and .'s problems)")
		return false
	}
	var user=matchArray[1]
	var domain=matchArray[2]
	// See if "user" is valid 
	if (user.match(userPat)==null) {
		// user is not valid
		alert("The Email username doesn't seem to be valid.")
		return false
	}
	// if the e-mail address is at an IP address (as opposed to a symbolic host name) make sure the IP address is valid. 
	var IPArray=domain.match(ipDomainPat)
	if (IPArray!=null) {
		// this is an IP address
		  for (var i=1;i<=4;i++) {
			if (IPArray[i]>255) {
				alert("The Email Destination IP address is invalid!")
			return false
			}
		}
		return true
	}
	// Domain is symbolic name
	var domainArray=domain.match(domainPat)
	if (domainArray==null) {
		alert("The Email domain name doesn't seem to be valid.")
		return false
	}
	/* Now we need to break up the domain to get a count of how many atoms it consists of. */
	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>4) {
	   // the address must end in a two letter or three letter word.
	   alert("The email address must end in a three-letter domain, or two letter country.")
	   return false
	}
	// Make sure there's a host name preceding the domain.
	if (len<2) {
	   var errStr="The Email address is missing a hostname!"
	   alert(errStr)
	   return false
	}
	return true;
}