function is_letters_and_or_digits(s) {
var letters_digits = /^[0-9a-zA-Z]+$/;
if (s.match(letters_digits)) {
return true;
}
else {
return false;
}
}
var s = "3.14";
document.write(is_letters_and_or_digits(s) + "<br />");
var s = "847";
document.write(is_letters_and_or_digits(s) + "<br />");
var s = "f35";
document.write(is_letters_and_or_digits(s) + "<br />");
var s = "abc 123";
document.write(is_letters_and_or_digits(s) + "<br />");
var s = "javascript";
document.write(is_letters_and_or_digits(s) + "<br />");
/*
run:
false
true
true
false
true
*/