function isnot_numeric(words,l){

var valid = "1234567890-()/ '";

if(words.value.length < l){
           
           return false;
}
for (var i=0; i< words.value.length; i++){
var temp = "" + words.value.substring(i,i+1);
if (valid.indexOf(temp) == "-1"){

return false;
}
}
return true;
}