function MediaTagRequest(loadItem, tag, srcAttribute) {
		this.AbstractRequest_constructor(loadItem);

		// protected properties
		this._tag = tag;
		this._tagSrcAttribute = srcAttribute;
		this._loadedHandler = createjs.proxy(this._handleTagComplete, this);
	}
An {{#crossLink "TagRequest"}}{{/crossLink}} that loads HTML tags for video and audio.
@class MediaTagRequest
@param {LoadItem} loadItem
@param {HTMLAudioElement|HTMLVideoElement} tag
@param {String} srcAttribute The tag attribute that specifies the source, such as "src", "href", etc.
@constructor