<HTML>

<HEAD>

<TITLE>TAVOLA PITAGORICA</TITLE>

<SCRIPT TYPE="text/javascript">

function pitagora() {

var num= parseInt(document.f.N.value);

var str= "";

for (i=1; i<=10; i++) {

str= str + i*num + " ";

}
document.write str;
}
</SCRIPT>

</HEAD>

<BODY>

<FORM NAME="f">

TABELLINA DEL:
<INPUT TYPE="TEXT" NAME="N">
<INPUT TYPE="BUTTON" VALUE="Esegui" ONCLICK="pitagora();">
</FORM>
</BODY>
</HTML>

mi dite cosa ho sbagliato?