function formfilter (input) {
stripit = document.form.phoneNumber.value;
filteredValues = ".()-/ ";  
var i;
var returnString = "";
for (i = 0; i < stripit.length; i++) {  
var c = stripit.charAt(i);
if (filteredValues.indexOf(c) == -1) returnString += c;
}
input.value = returnString;
}