//***controllo caratteri dannosi***
//special controlla che non vengano inseriti caratteri dannosi
//quotes non accetta gli apici
//notnumbers accetta solo numeri
var r={
  'all':/[\W & '\''&'\"' & ^\d]/g,
  'special':/[\W]/g,
  'onlyletters':/[^(a-zA-Z)]/g,
  'quotes':/['\''&'\"']/g,
  'reals':/[^\d,]/g,
  'notnumbers':/[^\d]/g
}

function valid(o,w){
  o.value = o.value.replace(r[w],'');
}
//***fine controllo caratteri dannosi***

//***inizio funzione limita caratteri
var ns6=document.getElementById&&!document.all

function restrictinput(maxlength,e,placeholder){
	if (window.event&&event.srcElement.value.length>=maxlength)
		return false
	else if (e.target&&e.target==eval(placeholder)&&e.target.value.length>=maxlength){
		var pressedkey=/[a-zA-Z0-9\.\,\/]/
		if (pressedkey.test(String.fromCharCode(e.which)))
			e.stopPropagation()
	}
}

function countlimit(maxlength,e,placeholder){
	var theform=eval(placeholder)
	var lengthleft=maxlength-theform.value.length
	var placeholderobj=document.all? document.all[placeholder] : document.getElementById(placeholder)
	if (window.event||e.target&&e.target==eval(placeholder)){
		if (lengthleft<0)
			theform.value=theform.value.substring(0,maxlength)
		placeholderobj.innerHTML=lengthleft
	}
}

function displaylimit(theform,thelimit){
	var limit_text='<b><span id="'+theform.toString()+'">'+thelimit+'</span></b> caratteri rimanenti'
	if (document.all||ns6)
		document.write(limit_text)
	if (document.all){
		eval(theform).onkeypress=function(){ return restrictinput(thelimit,event,theform)}
		eval(theform).onkeyup=function(){ countlimit(thelimit,event,theform); valid(this,'special')}
	}
	else if (ns6){
		document.body.addEventListener('keypress', function(event) { restrictinput(thelimit,event,theform) }, true); 
		document.body.addEventListener('keyup', function(event) { countlimit(thelimit,event,theform) }, true); 
	}
}
//***fine funzione limita caratteri