Usa esto ;) Yo lo tengo en varios sitios y funciona perfectamente ;)
Código PHP:
<%@LANGUAGE="VBSCRIPT"%>
<html>
<head>
<script language="JavaScript">
function currencyFormat(fld, milSep, decSep, e) {
var sep = 0;
var key = '';
var i = j = 0;
var len = len2 = 0;
var strCheck = '0123456789';
var aux = aux2 = '';
var whichCode = (window.Event) ? e.which : e.keyCode;
if (whichCode == 13) return true; // Enter
key = String.fromCharCode(whichCode); // Get key value from key code
if (strCheck.indexOf(key) == -1) return false; // Not a valid key
len = fld.value.length;
for(i = 0; i < len; i++)
if ((fld.value.charAt(i) != decSep)) break;
aux = '';
for(; i < len; i++)
if (strCheck.indexOf(fld.value.charAt(i))!=-1) aux += fld.value.charAt(i);
aux += key;
len = aux.length;
if (len == 0) fld.value = '';
if (len == 1) fld.value = aux;
if (len == 2){
if (aux>31)
window.alert("El dia debe ser inferior a 31");
else
fld.value = aux;
}
if (len > 2 && len < 5) {
if (len == 4){
if (aux.substr(len - 2, len)>12)
window.alert("El mes debe ser inferior a 12");
else
fld.value = aux;
}
aux2 = '';
for (j = 0, i = len - 3; i >= 0; i--) {
if (j == 2) {
aux2 += milSep;
j = 0;
}
aux2 += aux.charAt(i);
j++;
}
fld.value = '';
len2 = aux2.length;
for (i = len2 - 1; i >= 0; i--)
fld.value += aux2.charAt(i);
fld.value += decSep + aux.substr(len - 2, len);
}
if (len > 4 && len < 9) {
aux2 = '';
for (j = 0, i = len - 3; i >= 0; i--) {
if (j == 2 && i <= len -5) {
aux2 += milSep;
j = 0;
}
aux2 += aux.charAt(i);
j++;
}
fld.value = '';
len2 = aux2.length;
for (i = len2 - 1; i >= 0; i--)
fld.value += aux2.charAt(i);
fld.value += aux.substr(len - 2, len);
}
return false;
}
</script>
<title>Crear fecha de envio</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script language="JavaScript">
function currencyFormat(fld, milSep, decSep, e) {
var sep = 0;
var key = '';
var i = j = 0;
var len = len2 = 0;
var strCheck = '0123456789';
var aux = aux2 = '';
var whichCode = (window.Event) ? e.which : e.keyCode;
if (whichCode == 13) return true; // Enter
key = String.fromCharCode(whichCode); // Get key value from key code
if (strCheck.indexOf(key) == -1) return false; // Not a valid key
len = fld.value.length;
for(i = 0; i < len; i++)
if ((fld.value.charAt(i) != decSep)) break;
aux = '';
for(; i < len; i++)
if (strCheck.indexOf(fld.value.charAt(i))!=-1) aux += fld.value.charAt(i);
aux += key;
len = aux.length;
if (len == 0) fld.value = '';
if (len == 1) fld.value = aux;
if (len == 2){
if (aux>31)
window.alert("El dia debe ser inferior a 31");
else
fld.value = aux;
}
if (len > 2 && len < 5) {
if (len == 4){
if (aux.substr(len - 2, len)>12)
window.alert("El mes debe ser inferior a 12");
else
fld.value = aux;
}
aux2 = '';
for (j = 0, i = len - 3; i >= 0; i--) {
if (j == 2) {
aux2 += milSep;
j = 0;
}
aux2 += aux.charAt(i);
j++;
}
fld.value = '';
len2 = aux2.length;
for (i = len2 - 1; i >= 0; i--)
fld.value += aux2.charAt(i);
fld.value += decSep + aux.substr(len - 2, len);
}
if (len > 4 && len < 9) {
aux2 = '';
for (j = 0, i = len - 3; i >= 0; i--) {
if (j == 2 && i <= len -5) {
aux2 += milSep;
j = 0;
}
aux2 += aux.charAt(i);
j++;
}
fld.value = '';
len2 = aux2.length;
for (i = len2 - 1; i >= 0; i--)
fld.value += aux2.charAt(i);
fld.value += aux.substr(len - 2, len);
}
return false;
}
</script>
</head>
<body bgcolor="#0099CC" text="#000000">
<form name="form1" action="crear_fenvio2.asp">
<table width="50%" border="0">
<tr>
<td width="27%" bgcolor="#007CA6"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1" color="#FFFFFF">Ola:
</font></b></td>
<td width="73%">
<input type="text" name="nola">
</td>
</tr>
<tr>
<td width="27%" bgcolor="#007CA6"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1" color="#FFFFFF">Año:
</font></b></td>
<td width="73%">
<input type="text" name="anyo">
</td>
</tr>
<tr>
<td width="27%" bgcolor="#007CA6"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1" color="#FFFFFF">Fecha
de Envio:</font></b></td>
<td width="73%">
<input type="text" name="fenvio" onKeyPress="return(currencyFormat(this,'/','/',event))">
</td>
</tr>
<tr>
<td width="27%"> </td>
<td width="73%">
<input type="submit" name="Submit" value="Crear Fecha de Envio" onKeyPress="return(currencyFormat(this,'/','/',event))">
</td>
</tr>
</table>
<p> </p>
</form>
</body>
</html>