Updating a Date Column in SP2010 using Javascript in WP

Question

Hi,
I know that Today() doesn't work in SP. But seeing all the various JS codes to highlight rows etc is rather cumbersome, especially if you have several operations that you may want to run based on Today().
In my list, I have a column which is hidden from public view, 'thisDate'. This column is set to Date Only and with each new item that is added, it loads today's date. That's fine at item creation; but what I want to do is use JS to
update all fields in thisDate column with today's date whenever the list is first loaded on any new day.
<script type="text/javascript" language="javascript">
var tDate = null;
allItems = null;
ExecuteOrDelayUntilScriptLoaded(UpdateList, 'sp.js'); //this is necessary to ensure the library is loaded before function triggered
function DateThis(){
tDate = new Date().toJSON();
tDate.format("m/dd/yy");
return tDate;
function UpdateList(){
var tContext = new SP.ClientContext.get_current();
var tSite = tContext.get_site();
var tWeb = tSite.get_rootWeb();
var tList = tWeb.get_lists().getByTitle('TeamDUCOM LNO Travel');
var tQuery = SP.CamlQuery.createAllItemsQuery();
this.allItems = tList.getItems(tQuery);
tContext.load(allItems, 'Include(thisDate)');
tContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySuccess), Function.createDelegate(this, this.onQueryFailed));
function onQuerySuccess(){
var listEnum = allItems.getEnumerator();
var todaysDate = DateThis();
while(listEnum.moveNext()){
var currentItem = listEnum.get_current();
var origDate = currentItem.get_item('thisDate');
currentItem.set_item('thisDate',todaysDate);
currentItem.update();
tContext.executeQueryAsync(Function.createDelegate(this, this.ListItemsUpdateSuccess), Function.createDelegate(this, this.ListItemsUpdateFailed));
function onQueryFailed (){
alert('Query List Failed ');
function ListItemsUpdateSuccess(){
alert('Success ');
function ListItemsUpdateFailed(){
alert('Update List Failed ');
</script>
Right now, I get an 'onQueryFailed' alert saying the Query list failed.  Also in the watch windo, I get null for 'tDate and 'todaysDate' is undefined.
Once I can get this to work, it is my intention to add an extra line or two to compare variables
origDate with todaysDate. If they match, skip and go to next.  I think this would reduce updates and minimze the List sending out email alerts (most of my users use Alerts to be notified of changes to the list. (Bonus
would be being able to suspend any alert triggers at update, but I don't believe that's possible, or?)
After all the debugging, I also intend to comment out the alerts within the code, since no one needs to see that.
Ideally, this code would be reuseable on any list that needs countdowns, traffic lights, colorcoding etc, or even calcaulated columns using
thisDate data in lieu of the nonexistent Today()
function. And, as mentioned above, the list only needs to be updated once for the 1st person to open the list on any given day.
TIA
AH-C

Answer 1

Victoria,
That didn't work for me. When I stripped out the script tags fro the file and placed it around the script url, I kept getting an error message within the webpart while in page edit view: "Cannot retrieve the URL specified in the Content Link
property. For more assistance, contact your site administrator."
I tried both your suggested change and the older script every which way - before the list, after the list, hidden and not. I then focused more on the IE 9's F12 developer tool and watched as it stepped thru the code. Everything was fine with the variables
(each object loaded in the Locals view) until it came time to call the executeQueryAsync.
I even traced down the stack and confirming the arguments. But a thot kept bugging me about "get_rootweb". i had seen other examples where it was "get_web" instead. When I went back to search Bing, I came across an example where the coder
just cut to the chase, bypassing varibles (in my case, dropping 'tSite' & 'tWeb'), so my trimmed code snippet now looks like this:
var tContext = SP.ClientContext.get_current();
var tList = tContext.get_web().get_lists().getByTitle('MyList Name');
var tQuery = SP.CamlQuery.createAllItemsQuery();
this.everyItem = tList.getItems(tQuery);
Prior to that, I also changed the var 'allItems', because I wondered if that was causing conflicts, case-sensitivity notwithstanding, since my default list view was 'AllItems.aspx'
Anyway, it now works regardless of CEWP positioning/hidden status (using only the reference to JS file in SiteAssets and using the script tags within the js file, not the CWEP link) -- typically, I make such CWEPs (ie EasyTabs) hidden and at the bottom of
the page, after the list and it works just fine.
I'm going to mark this thread as answered. But before I do that, I'll work out the one piece I need to add for the code to do nothing to a particular item if 'todaysDate' matches 'origDate' then post the entire code as the solution.
Thanks again.
Best regards,
AH-C
PS, I got a deluge of email alerts telling me that the list was updated. I anticipated that and will be looking for code to stop that if possible.  But with the test for matching dates, at least I can limit the deluge of emails to once a day by whomever
is 1st to check the list that day (my alert is configured for instant alerting whenever a change has been made and I'd prefer to keep it that way, unless there's no workaround.