prototype: How to wrap an input field with span tag...

Hello everyone,

I am not at all a JavaScript expert so please bear with me.

Please have a look at the following code:

add_option_link.onclick = function() {
j++;

var tr = document.createElement("tr");

var td = document.createElement("td");
Element.insert(td, "Option " + j);
tr.appendChild(td);

var td = document.createElement("td");
var input = document.createElement("input");
input.name = "options["+i+"][option]["+j+"][display]";
Element.insert(td, input);
tr.appendChild(td);

var td = document.createElement("td");
var input = document.createElement("input");
input.name = "options["+i+"][option]["+j+"][option_number]";
Element.insert(td, input);
tr.appendChild(td);

var td = document.createElement("td");
var input = document.createElement("input");
input.name = "options["+i+"][option]["+j+"][price]";
Element.insert(td, input);
tr.appendChild(td);

var td = document.createElement("td");
var a = document.createElement("a");
a.href = "";
Element.insert(a, "delete");
a.onclick = function() {
tr = this.parentNode.parentNode;
Element.remove(tr);
return false;
}
Element.insert(td, a);
tr.appendChild(td);

Element.insert(options_table, tr);

return false;
}

This is obviously generating tr's and td's with input fields in them.

I would like the input field marked in red above (lines 25, 26) to be wrapped by <span> tags...

Hence, it should appear in HTML as follows:

<span id="sprytextfield1">
<input name="options[1][option][1][option_number]"/>
<span class="textfieldRequiredMsg">A value is required.</span></span>


I have no idea how to achieve this with the code above, and any help will be greatly appreciated.

Many thanks!