Prev/Next Buttons

Question

I am using some paging code to add a previous and next
buttons to my spry gallery. I am attempting (unsuccessfully) to
hide the previous button at the beginning of the recordset and the
next button at the end. I have pasted the code below if anyone has
any ideas.
<script language="JavaScript" type="text/javascript">
<!--
var pageOffset =0;
var pageSize = 5;
var pageStop = pageOffset + pageSize;
var dsGallery = new Spry.Data.XMLDataSet("images.xml",
"/gallery/photos/photo", { filterFunc: MyPagingFunc });
function MyPagingFunc(ds, row, rowNumber)
if (rowNumber < pageOffset || rowNumber >= pageStop)
return null;
return row;
function UpdatePage(offset)
var numRows = dsGallery.getUnfilteredData().length;
if (offset > (numRows - pageSize))
offset = numRows - pageSize;
if (offset < 0)
offset = 0;
pageOffset = offset;
pageStop = offset + pageSize;
// Re-apply our non-destructive filter on dsStates1:
dsGallery.filter(MyPagingFunc);
// Tell our 2nd region to update because we've adjusted
// some of the variables it uses in its spry:if expressions.
Spry.Data.updateRegion("list2");
// Change the XPath for the 3rd data set so that the 3rd
// region updates. Remember, position() starts at one and
not
// zero, so we have to add one to our pageOffset and
pageStop.
dsGallery.setXPath("/states/state[position() >=" +
(pageOffset+0) + " and position() < " + (pageStop+1) + "]");
-->
</script>
<input type="button" value="Prev"
onClick="UpdatePage(pageOffset - pageSize);" />
<input type="button" value="Next"
onClick="UpdatePage(pageOffset + pageSize);" />

Answer 1

why didn't you use Spry Paged View instead of writing your
own code?
then you can use
if ({ds_PageNumber} == 1 ) {
//disable prev button & enable next
else if ({ds_PageNumber} == {ds_PageCount} ) {
//disable next button & enable prev
else{
//enable both prev & next button
you then just have to call this function, every time you do
navigation or page load (using observer or anything else)