This function will download all of the files on a page. Use in dev console. Just tweak the selector to filter what types of links will be downloaded. Eliminates duplicate downloads. Requires jQuery. http://www.learningjquery.com/2009/04/better-stronger-safer-jquerify-bookmarklet

batchDownload.js

// requires jQuery
// tested only in Chrome console dev tools
// use jQuerify bookmarklet if your page doesn't have jQuery: http://www.learningjquery.com/2009/04/better-stronger-safer-jquerify-bookmarklet

function batchDownload( $jquery_collection_of_a_elements, buffer_ms, random_ms, timeonly_bool ){

	if( $jquery_collection_of_a_elements.length < 1 ){
		throw "Nothing to download! Empty jQuery collection.";
	}

	//optional time to wait between each download with an optional random time buffer to seem less automated. Use to avoid being banned for spamming a server.
	this.delay = {
		buffer: parseInt( buffer_ms ) || 500,
	};
	this.delay.random = parseInt( random_ms ) || this.delay.buffer;

	this.selector = $jquery_collection_of_a_elements.selector;//save our selector in case you are curious later.
	this.$files = $jquery_collection_of_a_elements;//$('.main-content li a[href$=".pdf"]');
	this.downloaded = {};//index of unique files
	this.unique = 0;//counts unique downloads
	this.complete = false;//not done yet

	this.lastfile = false;//whether the last file downloaded was successful or skipped.

	this.calculateDelay = function(){

		var itemdelay = this.delay.buffer + ( Math.ceil( Math.random() * this.delay.random ) );

		return itemdelay;
	}

	this.getFile = function(){

		var $currentFile = this.$files.eq(0);//get the first element in the collection

		$currentFile.attr('download','');//give the link a download attribute. This just makes thinks a lot less complicated than the iframe method of downloading stuff via javascript.

		var href = $currentFile.attr('href');//snag the link to the file

		if( typeof href === "undefined"){
			// jQuery element is not a link to a file because it has no href. Ignore.
			console.log( $currentFile[0] + ' is not a download link. Skipping...' );

			this.lastfile = false;

		} else {

			console.log('Requesting file ' + href );

			if( this.downloaded[ href ] ){
				// file has already been downloaded!
				console.log( 'That file has already been downloaded. Skipping...' );

				this.lastfile = false;

			} else {
				// the file has not been downloaded. download it.
				console.log( 'Download initiated for ' + href );
				this.unique++;//increment the number of unique downloads.
				this.downloaded[ href ] = true;
				$currentFile[0].click();//click the dom element to start the download.

				this.lastfile = true;

			}

		}

		this.$files = this.$files.not( $currentFile );//remove the link from our list so we don't try to download it again.

		if( this.$files.length > 0 ){//if we run out of links, stop.

			var that = this;
			var msdelay = this.lastfile ? this.calculateDelay() : 0;//if the last file was skipped, download this file without delay.

			this.currentTimeout = setTimeout( function(){
				that.getFile();//there are links left, so call this function again.
			}, msdelay );

		} else {
			console.log( 'Downloading complete. ' + this.unique + ' files downloaded.' );
			this.complete = true;
		}

	}

	this.go = this.start = this.begin = function(){
		this.getFile();//start
	};

	this.pause = this.stop = function(){
		if( typeof this.currentTimeout !== "undefined" ){
			clearTimeout( this.currentTimeout );
		}
	};

	this.delay.average = this.delay.buffer + this.delay.random / 2;
	this.delay.estimated = this.delay.average * this.$files.length;
	this.delay.minutes = Math.floor( this.delay.estimated / 1000 / 60 );
	this.delay.seconds = Math.floor( ( this.delay.estimated / 1000 / 60 - this.delay.minutes ) * 60 );

	console.log( this.$files.length + ' downloads queued (may include duplicates).');
	console.log( 'Estimated time to complete: ' + this.delay.minutes + ' minutes and ' + this.delay.seconds + ' seconds.' );

	if( !timeonly_bool ){
		// if we don't just want a time estimate, start the actual batch download.
		this.getFile();//start the first download.
	}

	return this;

}// end batchDownload().

// example usage:
var downloadAllPDFs = new batchDownload( $('a[href$=".pdf"]'), 250, 1000 );
// that's it!