validation - How do I make an input field accept only letters in javaScript?

Question

function validate() {
if(document.myForm.name.value =="" ){
alert("Enter a name");
document.myForm.name.focus();
return false;
}

This is what I've written it for an empty string, now i need it to accept only letters?

Answer 1

If you want only letters - so from a to z, lower case or upper case, excluding everything else (numbers, blank spaces, symbols), you can modify your function like this:

function validate() {
    if (document.myForm.name.value == "") {
        alert("Enter a name");
        document.myForm.name.focus();
        return false;
    }
    if (!/^[a-zA-Z]*$/g.test(document.myForm.name.value)) {
        alert("Invalid characters");
        document.myForm.name.focus();
        return false;
    }
}