[jQuery] Why keyCode into keyup event is disable

[Soledad]

I'm trying to use the folowing code

<!-- -------------------
HTML botom of the page
-------------------- -->
<script>initform()</script>

/*******
Javascript
*******/
function initform() {
// To find every input field into myform and attach mykeyupfct
        $("[EMAIL PROTECTED]'password']:visible,input
[EMAIL PROTECTED]'text']:visible").attr("id",function(){
                $(this).keyup(function()  {mykeyupfct(this);});
        })


}

function mykeyupfct(myfield) {
var sid="#"+myfield.id
var skey
$(sid).keyup(function(e) {
        skey = e.charCode ? e.charCode : e.keyCode ? e.keyCode : 0;
        alert("never alert : " + skey);
});

alert("always alert but no skey for "+sid);

}

Im also tryinng :
$(sid).bind('keyup', function(e) {skey=e.keyCode; alert(skey); })
but it's the same problem

Thank's a lot for your help

A beginner jQuery
Soledad