Validation checks if a required field has been left empty

The function below checks if a required field has been left empty. If the required field is blank, we return the error string to the main function. If it’s not blank, the function returns an empty string.

function validateEmpty(fld) {
var error = "";

if (fld.value.length == 0) {
fld.style.background = 'Yellow';
error = "The required field has not been filled in.\n"
} else {
fld.style.background = 'White';
}
return error;
}