Where is the problem in this prototype [ajax.Request] code ?

Question

  function sendM() {
new Ajax.Request("sendm.html", 
{ 
method: 'post', 
postBody: 'text='+ $F('text') +'&sub='+ $F('subject') +'&sname='+ $F('name') +'&sfmail='+ $F('email') +'to='+ $F('to'),
onLoading:showLoad,    
onComplete: showResponse
});
}
function showLoad(){
    $('dresult').innerHTML= "מבצע את הפעולה &nbsp;&nbsp;<br /><br />";
}

function showResponse(req){
    $('dresult').innerHTML= req.responseText;
}

The hTML Form code :

<form id="sfunc" name="sfunc" onsubmit="return false;">

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