codice:
<script language="Javascript">
function salva(p){
var arr = new Array();
for (var num=0;num<document.form1.numTable.value;num++)
{
arr[num] = num;
alert(arr[num]);
}

for (var i=0; i<document.form1.elements; i++) { 
var nomec = document.form1.elements[i].name; 
if(nomec.substr(0,1) == p) {
alert(nomec); <--------------------------NON CI ENTRA PROPRIO!!!!
                              }
                                            }
}
</script>

<body>
<form name="form1">
<input type="text" name="numTable" value="3">
<input type="text" name="1textfield1" value="1">

<input type="text" name="1textfield2" value="2">

<input type="text" name="1textfield3" value="3">

<input type="text" name="1textfield4" value="4">

<input type="text" name="1textfield5" value="5">

<input type="button" onClick="salva('1');" value="OK">
</form>