diff --git a/date_downloader.html b/date_downloader.html
index c56e58c..5ccff6b 100644
--- a/date_downloader.html
+++ b/date_downloader.html
@@ -5,130 +5,7 @@
   <link rel="stylesheet" href="jquery-ui.min.css">
   <script src="https://code.jquery.com/jquery-1.12.4.js"></script>
   <script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
-  <script>
-
-  var min_date = new Date(2015, 9-1, 1); //September 1, 2015
-  var max_date = "+0d"; //Today (zero days from today)
-  var depths = new Array(5, 25, 60);
-
-  $(document).ready(function() {
-
-    // create checkboxes for the depths
-    for(var i = 0; i < depths.length; i++) {
-        var container = $("#pick_depths");
-        var n = depths[i].toString() + 'cm';
-        var v = depths[i];
-        $('<input />', { type: 'checkbox', id: n, value: v, checked: 'checked' }).appendTo(container);
-        $('<label />', { 'for': n, text: n }).appendTo(container);
-    }
-
-    $("#outputs").tabs();
-
-    var startdt = $("#datepicker_start").datepicker({
-        dateFormat: "yy-mm-dd", 
-	//minDate: new Date(2015, 9-1, 1), 
-        minDate: min_date,
-	//maxDate: "+0D",
-        maxDate: max_date,
-        changeMonth: true,
-        changeYear: true,
-        onSelect: function(dt,inst){ 
-	    $("#blah").text(dt); 
-            enddt.datepicker("option", "minDate", dt);
-        }
-    });
-
-    var enddt = $("#datepicker_end").datepicker({
-        dateFormat: "yy-mm-dd", 
-        //minDate: new Date(2015, 9-1, 1), 
-        //maxDate: "+0D",
-        minDate: min_date,
-        maxDate: max_date,
-        changeMonth: true,
-        changeYear: true,
-        onSelect: function(dt,inst){ 
-	    $("#blah2").text(dt); 
-            startdt.datepicker("option", "maxDate", dt);
-            //$(this).change();
-        }
-    });
-
-    startdt.datepicker("setDate", min_date);
-    enddt.datepicker("setDate", max_date);
-
-    function make_date_array() {
-        var start_date = startdt.datepicker("getDate");
-        var end_date = enddt.datepicker("getDate");
-        var tmp_date = start_date;
-        var date_array = new Array();
-        while(tmp_date <= end_date) {
-            //
-            date_array.push(new Date(tmp_date));
-            tmp_date.setDate(tmp_date.getDate() + 1);
-        }
-        return date_array;
-    }
-
-    function vwc_raster_url(dt,depth) {
-        // dt: Date object
-        // depth: int
-        var dt_str = dt.toISOString().split('T')[0];
-        var url = 'http://soilmapnik.hpc.okstate.edu/' + dt_str + '/vwc/' + depth + '/raster.tif';
-        return url;
-    }
-
-    function vwc_filename(dt,depth) {
-        var dt_str = dt.toISOString().split('T')[0];
-        return 'raster_'+dt_str+'_vwc_'+depth+'cm.tif';
-    }
-
-    function make_link(url) {
-        return '<a href="'+url+'">'+url+'</a>';
-    }
-
-    function make_curl(url,file) {
-        return 'curl -o '+file+' '+url;
-    }
-
-    function make_wget(url,file) {
-        return 'wget -O - '+url+' > '+file;
-    }
-
-    $("#generate_urls").click(function(){
-        $("#urls").html(""); // clear existing urls
-        $("#curl").html("");
-        $("#wget").html("");
-        $("#download_list").html("");
-        var selected_dates = make_date_array();
-        var selected_depths = [];
-        for(var i=0; i<depths.length; i++) {
-            var elid = depths[i].toString() + 'cm';
-            document.getElementById(elid).checked && selected_depths.push(depths[i]);
-        }
-        /* Use all depths if no depths were selected  */
-        if(selected_depths.length == 0) {
-            selected_depths = depths.slice(); // copy the array
-        }
-        for(var i=0; i<selected_depths.length; i++) {
-            for(var j=0; j<selected_dates.length; j++) {
-                var u = vwc_raster_url(selected_dates[j], selected_depths[i]);
-                var f = vwc_filename(selected_dates[j], selected_depths[i]);
-                var link = make_link(u);
-                var curl = make_curl(u,f);
-                var wget = make_wget(u,f);
-                $("#urls").append(link + '<br/>\n');
-                $("#curl").append(curl + '<br/>\n');
-                $("#wget").append(wget + '<br/>\n');
-            }
-        }
-        $("#download_list").append('<a href="data:text/plain;charset=UTF-8,'+encodeURIComponent($("#urls").text())+'" download="vwc_links.txt">Links</a><br/>');
-        $("#download_list").append('<a href="data:text/plain;charset=UTF-8,'+encodeURIComponent($("#curl").text())+'" download="vwc_curl.txt">curl Commands</a><br/>');
-        $("#download_list").append('<a href="data:text/plain;charset=UTF-8,'+encodeURIComponent($("#wget").text())+'" download="vwc_wget.txt">wget Commands</a><br/>');
-    });
-
-  });
-
-  </script>
+  <script src="date_downloader.js"></script>
 </head>
 <body>
 
diff --git a/date_downloader.js b/date_downloader.js
new file mode 100644
index 0000000..51e7352
--- /dev/null
+++ b/date_downloader.js
@@ -0,0 +1,132 @@
+
+var min_date = new Date(2015, 9-1, 1); //September 1, 2015
+var max_date = "+0d"; //Today (zero days from today)
+var depths = new Array(5, 25, 60);
+
+$(document).ready(function() {
+
+    // create checkboxes for the depths
+    for(var i = 0; i < depths.length; i++) {
+        var container = $("#pick_depths");
+        var n = depths[i].toString() + 'cm';
+        var v = depths[i];
+        $('<input />', { type: 'checkbox', id: n, value: v, checked: 'checked' }).appendTo(container);
+        $('<label />', { 'for': n, text: n }).appendTo(container);
+    }
+
+    // setup jqueryui tabs for the output area
+    $("#outputs").tabs();
+
+    var startdt = $("#datepicker_start").datepicker({
+        dateFormat: "yy-mm-dd", 
+	//minDate: new Date(2015, 9-1, 1), 
+        minDate: min_date,
+	//maxDate: "+0D",
+        maxDate: max_date,
+        changeMonth: true,
+        changeYear: true,
+        onSelect: function(dt,inst){ 
+	    $("#blah").text(dt); 
+            enddt.datepicker("option", "minDate", dt);
+        }
+    });
+
+    var enddt = $("#datepicker_end").datepicker({
+        dateFormat: "yy-mm-dd", 
+        //minDate: new Date(2015, 9-1, 1), 
+        //maxDate: "+0D",
+        minDate: min_date,
+        maxDate: max_date,
+        changeMonth: true,
+        changeYear: true,
+        onSelect: function(dt,inst){ 
+	    $("#blah2").text(dt); 
+            startdt.datepicker("option", "maxDate", dt);
+            //$(this).change();
+        }
+    });
+
+    startdt.datepicker("setDate", min_date);
+    enddt.datepicker("setDate", max_date);
+
+    function make_date_array() {
+        var start_date = startdt.datepicker("getDate");
+        var end_date = enddt.datepicker("getDate");
+        var tmp_date = start_date;
+        var date_array = new Array();
+        while(tmp_date <= end_date) {
+            //push a copy of the date onto the array
+            //without the "new Date()" part, the entire array 
+            //ends up set to the last date
+            date_array.push(new Date(tmp_date));
+            tmp_date.setDate(tmp_date.getDate() + 1);
+        }
+        return date_array;
+    }
+
+    function vwc_raster_url(dt,depth) {
+        // dt: Date object
+        // depth: int
+        var dt_str = dt.toISOString().split('T')[0];
+        return 'http://soilmapnik.hpc.okstate.edu/'+dt_str+'/vwc/'+depth+'/raster.tif';
+    }
+
+    function vwc_filename(dt,depth) {
+        var dt_str = dt.toISOString().split('T')[0];
+        return 'raster_'+dt_str+'_vwc_'+depth+'cm.tif';
+    }
+
+    function make_link(url) {
+        return '<a href="'+url+'">'+url+'</a>';
+    }
+
+    function make_curl(url,file) {
+        return 'curl -o '+file+' '+url;
+    }
+
+    function make_wget(url,file) {
+        return 'wget -O - '+url+' > '+file;
+    }
+
+    $("#generate_urls").click(function(){
+        /* clear the exusting urls and download links */
+        $("#urls").html("");
+        $("#curl").html("");
+        $("#wget").html("");
+        $("#download_list").html("");
+
+        /* Get the selected depths and dates */
+        var selected_dates = make_date_array();
+        var selected_depths = [];
+        for(var i=0; i<depths.length; i++) {
+            var elid = depths[i].toString() + 'cm';
+            document.getElementById(elid).checked && selected_depths.push(depths[i]);
+        }
+
+        /* Use all depths if no depths were selected  */
+        if(selected_depths.length == 0) {
+            selected_depths = depths.slice(); // copy the array
+        }
+
+        /* Make download links, curl commands, and wget commands */
+        for(var i=0; i<selected_depths.length; i++) {
+            for(var j=0; j<selected_dates.length; j++) {
+                var u = vwc_raster_url(selected_dates[j], selected_depths[i]);
+                var f = vwc_filename(selected_dates[j], selected_depths[i]);
+                var link = make_link(u);
+                var curl = make_curl(u,f);
+                var wget = make_wget(u,f);
+                $("#urls").append(link + '<br/>\n');
+                $("#curl").append(curl + '<br/>\n');
+                $("#wget").append(wget + '<br/>\n');
+            }
+        }
+
+        /* Make links to download the URLs, curl commands, and wget commands as text files */
+        $("#download_list").append('<a href="data:text/plain;charset=UTF-8,'+encodeURIComponent($("#urls").text())+'" download="vwc_links.txt">Links</a><br/>');
+        $("#download_list").append('<a href="data:text/plain;charset=UTF-8,'+encodeURIComponent($("#curl").text())+'" download="vwc_curl.txt">curl Commands</a><br/>');
+        $("#download_list").append('<a href="data:text/plain;charset=UTF-8,'+encodeURIComponent($("#wget").text())+'" download="vwc_wget.txt">wget Commands</a><br/>');
+    });
+
+});
+