diff --git a/src/dzitilesource.js b/src/dzitilesource.js
index 633c0371..daed1f80 100644
--- a/src/dzitilesource.js
+++ b/src/dzitilesource.js
@@ -124,7 +124,7 @@ $.extend( $.DziTileSource.prototype, $.TileSource.prototype, /** @lends OpenSead
      * @function
      * @param {Object|XMLDocument} data - the raw configuration
      * @param {String} url - the url the data was retrieved from if any.
-     * @param {String} postData - data for the post request or null
+     * @param {String} postData - HTTP POST data in k=v&k2=v2... form; or null;
      * @return {Object} options - A dictionary of keyword arguments sufficient
      *      to configure this tile sources constructor.
      */
diff --git a/src/iiiftilesource.js b/src/iiiftilesource.js
index 1bcc565b..dfa10c8e 100644
--- a/src/iiiftilesource.js
+++ b/src/iiiftilesource.js
@@ -184,7 +184,7 @@ $.extend( $.IIIFTileSource.prototype, $.TileSource.prototype, /** @lends OpenSea
      * @function
      * @param {Object} data - the raw configuration
      * @param {String} url - the url configuration was retrieved from
-     * @param {String} postData - data for the post request or null
+     * @param {String} postData - HTTP POST data in k=v&k2=v2... form; or null;
      * @example <caption>IIIF 1.1 Info Looks like this</caption>
      * {
      *   "@context" : "http://library.stanford.edu/iiif/image-api/1.1/context.json",
diff --git a/src/imageloader.js b/src/imageloader.js
index b48e1d55..dc92e4ea 100644
--- a/src/imageloader.js
+++ b/src/imageloader.js
@@ -43,7 +43,7 @@
  * @param {String} [options.loadWithAjax] - Whether to load this image with AJAX.
  * @param {String} [options.ajaxHeaders] - Headers to add to the image request if using AJAX.
  * @param {String} [options.crossOriginPolicy] - CORS policy to use for downloads
- * @param {String} [options.postData] - POST parameters or null
+ * @param {String} [options.postData] - HTTP POST data in k=v&k2=v2... form; or null
  * @param {Function} [options.callback] - Called once image has been downloaded.
  * @param {Function} [options.abort] - Called when this image job is aborted.
  * @param {Number} [options.timeout] - The max number of milliseconds that this image job may take to complete.
diff --git a/src/imagetilesource.js b/src/imagetilesource.js
index cc0d2619..462c33a4 100644
--- a/src/imagetilesource.js
+++ b/src/imagetilesource.js
@@ -89,7 +89,7 @@
          * @function
          * @param {Object} options - the options
          * @param {String} dataUrl - the url the image was retrieved from, if any.
-         * @param {String} postData - data for the post request or null
+         * @param {String} postData - HTTP POST data in k=v&k2=v2... form; or null
          * @return {Object} options - A dictionary of keyword arguments sufficient
          *      to configure this tile sources constructor.
          */
diff --git a/src/legacytilesource.js b/src/legacytilesource.js
index cdf0cbc9..ab544eb1 100644
--- a/src/legacytilesource.js
+++ b/src/legacytilesource.js
@@ -122,7 +122,7 @@ $.extend( $.LegacyTileSource.prototype, $.TileSource.prototype, /** @lends OpenS
      * @function
      * @param {Object|XMLDocument} configuration - the raw configuration
      * @param {String} dataUrl - the url the data was retrieved from if any.
-     * @param {String} postData - data for the post request or null
+     * @param {String} postData - HTTP POST data in k=v&k2=v2... form; or null
      * @return {Object} options - A dictionary of keyword arguments sufficient
      *      to configure this tile sources constructor.
      */
diff --git a/src/osmtilesource.js b/src/osmtilesource.js
index d5a11163..fcfe5c30 100644
--- a/src/osmtilesource.js
+++ b/src/osmtilesource.js
@@ -122,7 +122,7 @@ $.extend( $.OsmTileSource.prototype, $.TileSource.prototype, /** @lends OpenSead
      * @function
      * @param {Object} data - the raw configuration
      * @param {String} url - the url the data was retrieved from if any.
-     * @param {String} postData - data for the post request or null
+     * @param {String} postData - HTTP POST data in k=v&k2=v2... form; or null
      * @return {Object} options - A dictionary of keyword arguments sufficient
      *      to configure this tile sources constructor.
      */
diff --git a/src/tile.js b/src/tile.js
index ba4a5575..a427e137 100644
--- a/src/tile.js
+++ b/src/tile.js
@@ -50,7 +50,7 @@
  * @param {Boolean} loadWithAjax Whether this tile image should be loaded with an AJAX request .
  * @param {Object} ajaxHeaders The headers to send with this tile's AJAX request (if applicable).
  * @param {OpenSeadragon.Rect} sourceBounds The portion of the tile to use as the source of the
- * @param {String} postData post parameters or null
+ * @param {String} postData HTTP POST data in k=v&k2=v2... form; or null
  * drawing operation, in pixels. Note that this only works when drawing with canvas; when drawing
  * with HTML the entire tile is always used.
  */
@@ -101,7 +101,7 @@ $.Tile = function(level, x, y, bounds, exists, url, context2D, loadWithAjax, aja
     /**
      * Post parameters for this tile. Either it is an URL-encoded string
      * in k1=v1&k2=v2... format or null
-     * @member {String} postData
+     * @member {String} postData HTTP POST data in k=v&k2=v2... form; or null
      * @memberof OpenSeadragon.Tile#
      */
     this.postData  = postData;
diff --git a/src/tilesource.js b/src/tilesource.js
index c6517fda..60535eea 100644
--- a/src/tilesource.js
+++ b/src/tilesource.js
@@ -550,7 +550,7 @@ $.TileSource.prototype = {
                      * @property {OpenSeadragon.TileSource} eventSource - A reference to the TileSource which raised the event.
                      * @property {String} message
                      * @property {String} source
-                     * @property {String} postData or null
+                     * @property {String} postData - HTTP POST data in k=v&k2=v2... form; or null
                      * @property {?Object} userData - Arbitrary subscriber-defined object.
                      */
                     _this.raiseEvent( 'open-failed', {
@@ -593,7 +593,8 @@ $.TileSource.prototype = {
      * @param {String|Object|Array|Document} data
      * @param {String} url - the url the data was loaded
      *      from if any.
-     * @param {String} postData value obtained from the url after '#' sign or null
+     * @param {String} postData - HTTP POST data in k=v&k2=v2... form; or null; value obtained from
+     *      the protocol URL after '#' sign if flag splitHashDataForPost set to 'true'
      * @return {Object} options - A dictionary of keyword arguments sufficient
      *      to configure the tile source constructor (include all values you want to
      *      instantiate the TileSource subclass with - what _options_ object should contain).
diff --git a/src/tmstilesource.js b/src/tmstilesource.js
index 355ffa99..e9eef83b 100644
--- a/src/tmstilesource.js
+++ b/src/tmstilesource.js
@@ -111,7 +111,7 @@ $.extend( $.TmsTileSource.prototype, $.TileSource.prototype, /** @lends OpenSead
      * @function
      * @param {Object} data - the raw configuration
      * @param {String} url - the url the data was retrieved from if any.
-     * @param {String} postData - data for the post request or null
+     * @param {String} postData - HTTP POST data in k=v&k2=v2... form; or null
      * @return {Object} options - A dictionary of keyword arguments sufficient
      *      to configure this tile sources constructor.
      */
diff --git a/src/zoomifytilesource.js b/src/zoomifytilesource.js
index 540b2695..ce90aba8 100644
--- a/src/zoomifytilesource.js
+++ b/src/zoomifytilesource.js
@@ -122,7 +122,7 @@
          * @function
          * @param {Object} data - the raw configuration
          * @param {String} url - the url the data was retrieved from if any.
-         * @param {String} postData - data for the post request or null
+         * @param {String} postData - HTTP POST data in k=v&k2=v2... form; or null
          * @return {Object} options - A dictionary of keyword arguments sufficient
          *      to configure this tile sources constructor.
          */