function findChar(argvalue, lookFor) {
     argvalue = argvalue.toString();
      for (var n = 0; n < argvalue.length; n++) {
            if (argvalue.substring(n, n+1) == lookFor)
                  return true;
    }
      return false;
}

function checkEmail(sField, sItemName){
	var tempField = eval("document.forms.form1." + sField + ".value")      //puts together ie. document.forms.form1.txtCustomerName.value
	var sErrorString = "";
	//'-------validate that email is not empty has a "." and an "@" sign 
      if (tempField == "") { 
            sErrorString = "The " + sItemName + " field cannot be blank.\n";
     } else {
        var foundChar = findChar(tempField, ".");
        if (foundChar  == false) {   // 'if couldn't find a "." in the email address (invalid)
            sErrorString = "The " + sItemName + " field is invalid.\n";
        } else { 
            foundChar = findChar(tempField, "@");
            if (foundChar == false)    //if couldn't find an "@" in the email address (invalid)
                sErrorString = "The " + sItemName + " field is invalid.\n";
        }
    }	
	return sErrorString;
}

function validate() {
	var sErrorString = "";  
	//validate email addresses 
	sErrorString = checkEmail("yourEmail","Your Email");
	sErrorString = sErrorString + checkEmail("friendsEmail","Friend's Email");
	
	
    //if errors display msgbox and don't navigate to next page 
    if (sErrorString != "") {
        alert(sErrorString);
        return false; 
    }
    return true;    
}

function validateNotFoundEmail() {
	var sErrorString = "";  
	//validate email addresses 
	sErrorString = checkEmail("txtNotFoundEmail","Email Address");		
    //if errors display msgbox and don't navigate to next page 
    if (sErrorString != "") {
        alert(sErrorString);
        return false; 
    }
    return true;    
}