Just few random notes on Parse and Mobile FileUpload

FileUpload on mobile

 <input type="file" accept="image/*">

Android (Chrome and 4.4 native) provides a reasonable, but not-pretty, interface.

If you want to use camera, add the capture camera option. Note that it will not allow other images.

Parse.com allows to upload the file and query it by URL. It`s very simple, but note that it means an image access counts as an API call, and as images usually come in packs, this can cost your quota.

Detect change on textarea

Use $('#textAreaId#).on('change',function() { do something here });

change will be called when the focus is changed and any of the inside-text change.

Parse model update

On many views, you will want to first refresh the view from a saved DB element, and then on edit update(re-save) the element and refresh the view again.

For this pattern, always keep a cached parse object which was returned from the DB and is connected to parse via the row-id.
On refresh, update the cached-element, if found in the DB.
On edit either re-save (on the cached one) if it already exists, or save a new one and create cache.

You can save multiple objects via Parse.Object.saveAll (array)

Parse queries

When querying a pointer, sadly, you can't just pass an instance of a previously returned item (item itself != item pointer). You have to create a pointer object. 

var pointerToUser = {  __type: "Pointer",  className: "_User",       objectId: myUserItem.id };

You can combine multiple queries using Query.or(q1, q2)

Parse weird save/query results

• Parse will not fail if you query a db class which do not exist at all. Beware of Parse.Object.extend("SpellingMistakeWillNotBeNoticed");
• It will also allow you to save db columns which do not exist at all. Beware of (item.set('spellingMistake',666).