function changeopac(cur)
{
if (cur.style.MozOpacity)
   {
   if (cur.style.MozOpacity==1){cur.style.MozOpacity=0.5;}
   else if (cur.style.MozOpacity==0.5){cur.style.MozOpacity=1;}
   }
else if (cur.filters)
   {
   if (cur.filters.alpha.opacity==100){cur.filters.alpha.opacity=50;}
   else if (cur.filters.alpha.opacity==50){cur.filters.alpha.opacity=100;}
   }
}

<!--vérif des caractères interdits inférieur et supérieur-->
function carcheck(formpart)
{
var car1=">"
var car2="<"
if (formpart.value.search(car1)==-1 && formpart.value.search(car2)==-1)
    return true
else
    alert("Vous avez tap&eacute; un caractère interdit (< >)\nRecommencez. Merci\n\n (Le curseur va se placer dans le champ concern&eacute;)") 
    formpart.focus(); 
    return false; 
}

<!-- C H E C K _ R E S A -->
function check_resa(form_name)
{
if (checknom(form_name) && checkemail(form_name) && checktel(form_name)){document[form_name].submit();}
else return false;
}

<!-- C H E C K _ G B -->
function check_gb(form_name)
{
if (checktitre(form_name) && checkcorps(form_name) && checknom(form_name) && checkemail(form_name)){document[form_name].submit();}
else return false;
}

<!-- C H E C K _ C O N T A C T -->
function check_contact(form_name)
{
if (checkcorps(form_name) && checknom(form_name) && checkemail(form_name)){document[form_name].submit();}
else return false;
}

<!-- C H E C K T I T R E -->
function checktitre(form_name)
{
if (document[form_name].titre.value == "") { 
    alert("\nVeuillez saisir le titre de votre message\nPlease type the title of your message") 
    document[form_name].titre.focus(); 
    return false; 
	}
else {
	 if (carcheck(document[form_name].titre))
	 return true;
	 }	
}

<!-- C H E C K C O R P S -->
function checkcorps(form_name)
{
if (document[form_name].corps.value == "") { 
    alert("\nVeuillez saisir votre message\nPlease type your message") 
    document[form_name].corps.focus(); 
    return false; 
	}
else {
	 if (carcheck(document[form_name].corps))
	 return true;
	 }	
}

<!-- C H E C K N O M -->
function checknom(form_name)
{
if (document[form_name].nom.value == "") { 
    alert("\nVeuillez saisir votre nom\nPlease type your name") 
    document[form_name].nom.focus(); 
    return false; 
	}
else {
	 if (carcheck(document[form_name].nom))
	 return true;
	 }	
}

<!-- C H E C K E M A I L -->
function checkemail(form_name)
{
if (document[form_name].email.value == "") { 
    alert("\nVeuillez saisir votre adresse email\nPlease type your email address") 
    document[form_name].email.focus(); 
    return false; 
	}
else {
	 if (isEmail(document[form_name].email.value)) {
	 											   if (carcheck(document[form_name].email))
	 											  return true;
												  }
	else {
    alert("\nVeuillez saisir une adresse email valide\nPlease type a valid email address")
    document[form_name].email.focus(); 
	return false;
	} 
	 }
	 	
}

<!-- I S E M A I L -->
function isEmail(str) {
  // are regular expressions supported?
  var supported = 0;
  if (window.RegExp) {
    var tempStr = "a";
    var tempReg = new RegExp(tempStr);
    if (tempReg.test(tempStr)) supported = 1;
  }
  if (!supported) 
    return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
  var r1 = new RegExp("(@.*@)|(\\.\\.)|(@\\.)|(^\\.)");
  var r2 = new RegExp("^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$");
  return (!r1.test(str) && r2.test(str));
}

<!-- C H E C K T E L -->
function checktel(form_name)
{
if (document[form_name].tel.value == "") { 
    alert("\nVeuillez saisir votre numero de telephone\nPlease type your phone number") 
    document[form_name].tel.focus(); 
    return false; 
	}
else 
	 {	
	 if (document[form_name].tel.value != "" && document[form_name].tel.value.replace(/\D/g,'') == "")
	 {
    alert("\nVeuillez saisir un numero de telephone valide\nPlease type a valid phone number") 
    document[form_name].tel.focus(); 
    return false; 
	 }
	 else {
	 	  if (carcheck(document[form_name].tel))
	 	  return true;
		  }
	 }
}