or also
<input type="text" onkeypress="handleNumber(event, '€ {-10,3} $')" placeholder="€ $" size=25>
with
function handleNumber(event, mask) {
/* numeric mask with pre, post, minus sign, dots and comma as decimal separator
{}: positive integer
{10}: positive integer max 10 digit
{,3}: positive float max 3 decimal
{10,3}: positive float max 7 digit and 3 decimal
{null,null}: positive integer
{10,null}: positive integer max 10 digit
{null,3}: positive float max 3 decimal
{-}: positive or negative integer
{-10}: positive or negative integer max 10 digit
{-,3}: positive or negative float max 3 decimal
{-10,3}: positive or negative float max 7 digit and 3 decimal
*/
with (event) {
stopPropagation()
preventDefault()
if (!charCode) return
var c = String.fromCharCode(charCode)
if (c.match(/[^-\d,]/)) return
with (target) {
var txt = value.substring(0, selectionStart) + c + value.substr(selectionEnd)
var pos = selectionStart + 1
}
}
var dot = count(txt, /\./, pos)
txt = txt.replace(/[^-\d,]/g,'')
var mask = mask.match(/^(\D*)\{(-)?(\d*|null)?(?:,(\d+|null))?\}(\D*)$/); if (!mask) return // meglio exception?
var sign = !!mask[2], decimals = +mask[4], integers = Math.max(0, +mask[3] - (decimals || 0))
if (!txt.match('^' + (!sign?'':'-?') + '\\d*' + (!decimals?'':'(,\\d*)?') + '$')) return
txt = txt.split(',')
if (integers && txt[0] && count(txt[0],/\d/) > integers) return
if (decimals && txt[1] && txt[1].length > decimals) return
txt[0] = txt[0].replace(/\B(?=(\d{3})+(?!\d))/g, '.')
with (event.target) {
value = mask[1] + txt.join(',') + mask[5]
selectionStart = selectionEnd = pos + (pos==1 ? mask[1].length : count(value, /\./, pos) - dot)
}
function count(str, c, e) {
e = e || str.length
for (var n=0, i=0; i<e; i+=1) if (str.charAt(i).match(c)) n+=1
return n
}
}