A related question about JS, ask the Master to solve

A question about JS, ask the Master to solve.
I have two JS-written functions:
A function verifies that user input is incorrect, incorrect alert ("error")
Specific as follows:
function A ()
{
if (document.form.username.value! = ") {
Alert ("Error");
return false;
}
}
The A function is then called in the B function:
function B ()
{
return a ();
Form.submit ();
}
In this way, when the commit is called the B function to do other functions, and then call a function, of course, I use the above B function in the way called when the username is empty when there is a hint, the page is not submitted,
The problem is that when username is not empty, page-point submissions have no response or commit.

When I call a function in the B function "Return" is taken out, the input is empty prompt error, and then submitted to the next page, I want to have a problem on this page do not submit, input is not empty to submit to the next page, there is a master to see what the problem????


Thank you

------Solution--------------------
function B ()
{
if (A ()) Form.submit ();
return false;
}

