function esString(e) {
var charCode
var charCode
if (navigator.appName == "Netscape")
    charCode = e.which
else
    charCode = e.keyCode
    status = charCode
if  ((charCode < 13 || charCode > 13) && (charCode < 32 || charCode > 32) && (charCode < 45 || charCode > 46) && (charCode < 48 || charCode > 57) && (charCode < 97 || charCode > 122) && (charCode < 65 || charCode > 90)&& (charCode < 209 || charCode > 209)&& (charCode < 241 || charCode > 241)){
    alert("Caracter no Valida!!")
    return false
}else{
}
return true
}