diff --git a/dist/fallwall.min.js b/dist/fallwall.min.js
index 426130e..e7d5612 100644
--- a/dist/fallwall.min.js
+++ b/dist/fallwall.min.js
@@ -1,8 +1,8 @@
-"use strict";var _typeof="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e};/*!
+"use strict";var _extends=Object.assign||function(r){for(var e=1;e<arguments.length;e++){var n=arguments[e];for(var t in n)Object.prototype.hasOwnProperty.call(n,t)&&(r[t]=n[t])}return r},_typeof="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(r){return typeof r}:function(r){return r&&"function"==typeof Symbol&&r.constructor===Symbol&&r!==Symbol.prototype?"symbol":typeof r};/*!
  * Fallwall.js
  *
  * Copyright © 2017 Eddie Wen | MIT license
  * https://github.com/EddieWen-Taiwan/Fallwall.js
  */
-!function(e,n){"object"===("undefined"==typeof exports?"undefined":_typeof(exports))&&"undefined"!=typeof module?module.exports=n(require("jquery")):"function"==typeof define&&define.amd?define(["jquery"],n):e.Fallwall=n(jQuery)}(void 0,function(e){var n={},r=function(e,r){for(var o=0;o<n.gridNumber&&"undefined"!=typeof e[o];o++)t(e[o],"down"),n.currentGrid=o;r&&("function"==typeof r?r():console.error(r+" is not a function"))},t=function(r,t){for(var i=n.html_template,f=0;f<Object.keys(r).length;f++)i=i.replace("fallwall_#"+(f+1),r[f]);var u,d=e(".fw_column").eq(o());"up"==t?(d.prepend(i),u=d.find(".fw_grid").first()):(d.append(i),u=d.find(".fw_grid").last()),""!=n.defaultClass&&u.addClass(n.defaultClass)},o=function(){var n=[];e.each(e(".fw_column"),function(e,r){n.push(r.offsetHeight)});var r=Math.min.apply(null,n);return e.inArray(r,n)};e.fn.fallwall_init=function(t,o,i,f){if(null==t||null==o)throw new Error("You missed some parameters while initializing");n=e.extend({gridNumber:20,columnNumber:1,defaultClass:"",html_template:"<div class='fw_grid'>"+t+"</div>",dataArray:o,currentGrid:0},i);for(var u="",d=0;d<n.columnNumber;d++)u+="<div class='fw_column'></div>";this.append(u),this.find(".fw_column").css({display:"inline-block","vertical-align":"top",width:100/n.columnNumber+"%"}),r(o,f)},e.fn.loadMoreFw=function(e){if(n.currentGrid+1<n.dataArray.length){n.currentGrid++;for(var r=n.currentGrid+n.gridNumber,o=n.currentGrid;o<r;o++){if("undefined"==typeof n.dataArray[o])return e&&("function"==typeof e?e():console.error(e+" is not a function")),"NO_MORE_DATA";if(t(n.dataArray[o],"down"),n.currentGrid=o,o==r-1)return e&&("function"==typeof e?e():console.error(e+" is not a function")),"FINISHED"}}return"NO_MORE_DATA"},e.fn.addFwGrid=function(e,n){if("object"!=("undefined"==typeof e?"undefined":_typeof(e)))throw new Error("First parameter of addFwGrid(): "+e+" must be Object");t(e,"up"),n&&("function"==typeof n?n():console.error(n+" is not a function"))}});
+!function(r,e){"object"===("undefined"==typeof exports?"undefined":_typeof(exports))&&"undefined"!=typeof module?module.exports=e(require("jquery")):"function"==typeof define&&define.amd?define(["jquery"],e):r?r.Fallwall=e(jQuery):window.Fallwall=e(jQuery)}(void 0,function(r){var e={gridNumber:20,columnNumber:1,defaultClass:"",currentGrid:0},n=function(r,n){for(var o=0;o<e.gridNumber&&"undefined"!=typeof r[o];o++)t(r[o],"down"),e.currentGrid=o;n&&("function"==typeof n?n():console.error(n+" is not a function"))},t=function(n,t){for(var i=e.html_template,f=0;f<Object.keys(n).length;f++)i=i.replace("fallwall_#"+(f+1),n[f]);var a,u=r(".fw_column").eq(o());"up"==t?(u.prepend(i),a=u.find(".fw_grid").first()):(u.append(i),a=u.find(".fw_grid").last()),""!=e.defaultClass&&a.addClass(e.defaultClass)},o=function(){var e=[];r.each(r(".fw_column"),function(r,n){e.push(n.offsetHeight)});var n=Math.min.apply(null,e);return r.inArray(n,e)};r.fn.fallwall_init=function(r,t,o,i){if(console.log(this),!r)throw new Error("missed HTML template");if(!t)throw new Error("missed data source");if(!Array.isArray(t))throw new Error("typeof dataArray is not correct");e=_extends({},e,{html_template:"<div class='fw_grid'>"+r+"</div>",dataArray:t},o);for(var f="",a=0;a<e.columnNumber;a++)f+="<div class='fw_column'></div>";this.append(f),this.find(".fw_column").css({"vertical-align":"top",display:"inline-block",width:Math.floor(1e3/e.columnNumber)/10+"%"}),n(t,i)},r.fn.loadMoreFw=function(r){if(e.currentGrid+1<e.dataArray.length){e.currentGrid++;for(var n=e.currentGrid+e.gridNumber,o=e.currentGrid;o<n;o++){if("undefined"==typeof e.dataArray[o])return r&&("function"==typeof r?r():console.error(r+" is not a function")),"NO_MORE_DATA";if(t(e.dataArray[o],"down"),e.currentGrid=o,o==n-1)return r&&("function"==typeof r?r():console.error(r+" is not a function")),"FINISHED"}}return"NO_MORE_DATA"},r.fn.addFwGrid=function(r,e){if("object"!=("undefined"==typeof r?"undefined":_typeof(r)))throw new Error("First parameter of addFwGrid(): "+r+" must be Object");t(r,"up"),e&&("function"==typeof e?e():console.error(e+" is not a function"))}});
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diff --git a/dist/fallwall.min.js.map b/dist/fallwall.min.js.map
index b762258..ec27ea8 100644
--- a/dist/fallwall.min.js.map
+++ b/dist/fallwall.min.js.map
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i < defaults.gridNumber; i++ ) {\n\t\t\tif( typeof dataArray[i] != \"undefined\" ) {\n\t\t\t\t_appendGrids( dataArray[i], 'down' );\n\t\t\t\tdefaults.currentGrid = i;\n\t\t\t}\n\t\t\telse {\n\t\t\t\tbreak;\n\t\t\t}\n\t\t}\n\n\t\tif( callback_func ) {\n\t\t\tif( typeof callback_func == 'function' )\n\t\t\t\tcallback_func();\n\t\t\telse\n\t\t\t\tconsole.error(callback_func+' is not a function');\n\t\t}\n\n\t},\n\n\t/**\n\t * Add new grid\n\t * direction: up/down => grid is added at the top/bottom\n\t */\n\t_appendGrids = function( obj, direction ) {\n\n\t\tvar thisCode = defaults.html_template;\n\n\t\tfor( var j = 0; j < Object.keys(obj).length; j++ ) {\n\t\t\tthisCode = thisCode.replace( 'fallwall_#'+(j+1), obj[j] );\n\t\t}\n\n\t\tvar targetColumn = $('.fw_column').eq( _getShortestColumn() );\n\t\tvar creatingElement;\n\t\tif( direction == 'up' ) {\n\t\t\ttargetColumn.prepend( thisCode );\n\t\t\tcreatingElement = targetColumn.find('.fw_grid').first();\n\t\t}\n\t\telse {\n\t\t\ttargetColumn.append( thisCode );\n\t\t\tcreatingElement = targetColumn.find('.fw_grid').last();\n\t\t}\n\n\t\t/**\n\t\t * Add extra class\n\t\t * like animation class\n\t\t */\n\t\tif( defaults.defaultClass != '' ) {\n\t\t\tcreatingElement.addClass( defaults.defaultClass );\n\t\t}\n\n\t},\n\n\t/**\n\t * Return the shortest fw_column to append a new grid\n\t */\n\t_getShortestColumn = function() {\n\n\t\tvar heightArray = [];\n\n\t\t$.each( $('.fw_column'), function(index, element) {\n\t\t\theightArray.push( element.offsetHeight );\n\t\t});\n\n\t\tvar minColumn = Math.min.apply( null, heightArray );\n\t\treturn $.inArray( minColumn, heightArray );\n\n\t};\n\n\t/**\n\t * Fallwall construtcor\n\t * Setup template and data source\n\t */\n\t$.fn.fallwall_init = function( template, dataArray, options, callbackFunction ) {\nconsole.log(this);\n\t\t/**\n\t\t * check required parameters\n\t\t */\n\t\tif( !template ) {\n\t\t\tthrow new Error('missed HTML template');\n\t\t}\n\n\t\tif( !dataArray ) {\n\t\t\tthrow new Error('missed data source');\n\t\t}\n\t\tif( !Array.isArray(dataArray) ) {\n\t\t\tthrow new Error('typeof dataArray is not correct');\n\t\t}\n\n\t\t// Store data from user\n\t\tdefaults = {\n\t\t\t...defaults,\n\t\t\thtml_template: `<div class='fw_grid'>${template}</div>`,\n\t\t\tdataArray: dataArray,\n\t\t\t...options,\n\t\t};\n\n\t\t// Add columns\n\t\tlet colElements = '';\n\t\tfor( let i = 0; i < defaults.columnNumber; i++ ) {\n\t\t\tcolElements += '<div class=\\'fw_column\\'></div>';\n\t\t}\n\t\tthis.append( colElements );\n\n\t\t// Prepare CSS\n\t\tthis.find('.fw_column').css({\n\t\t\t'vertical-align': 'top',\n\t\t\tdisplay: 'inline-block',\n\t\t\twidth: `${Math.floor(1000/defaults.columnNumber)/10}%`,\n\t\t});\n\n\t\t// Add grids at first\n\t\t_setFirstRoundContent( dataArray, callbackFunction );\n\n\t};\n\n\t/**\n\t * load more data and append them\n\t */\n\t$.fn.loadMoreFw = function( callback_func ) {\n\n\t\tif( defaults.currentGrid +1 < defaults.dataArray.length ) {\n\n\t\t\tdefaults.currentGrid++;\n\t\t\tvar limitNum = defaults.currentGrid + defaults.gridNumber;\n\t\t\tfor( var i = defaults.currentGrid; i < limitNum; i++ ) {\n\n\t\t\t\tif( typeof defaults.dataArray[i] != \"undefined\" ) {\n\n\t\t\t\t\t_appendGrids( defaults.dataArray[i], 'down' );\n\t\t\t\t\tdefaults.currentGrid = i;\n\n\t\t\t\t}\n\t\t\t\telse {\n\t\t\t\t\t// Data is exhausted before last run in loop\n\t\t\t\t\tif( callback_func ) {\n\t\t\t\t\t\tif( typeof callback_func == 'function' )\n\t\t\t\t\t\t\tcallback_func();\n\t\t\t\t\t\telse\n\t\t\t\t\t\t\tconsole.error(callback_func+' is not a function');\n\t\t\t\t\t}\n\t\t\t\t\treturn \"NO_MORE_DATA\";\n\t\t\t\t}\n\n\t\t\t\t// Last run in loop\n\t\t\t\tif( i == limitNum-1 ) {\n\t\t\t\t\tif( callback_func ) {\n\t\t\t\t\t\tif( typeof callback_func == 'function' )\n\t\t\t\t\t\t\tcallback_func();\n\t\t\t\t\t\telse\n\t\t\t\t\t\t\tconsole.error(callback_func+' is not a function');\n\t\t\t\t\t}\n\t\t\t\t\treturn \"FINISHED\";\n\t\t\t\t}\n\n\t\t\t}\n\n\t\t}\n\n\t\t/***\n\t\t * There is no more data.\n\t\t * All is displayed.\n\t\t***/\n\t\treturn \"NO_MORE_DATA\";\n\n\t};\n\n\t/**\n\t * directly append a new grid at the top of one column\n\t */\n\t$.fn.addFwGrid = function( data, callback_func ) {\n\n\t\tif( typeof data == 'object' ) {\n\t\t\t// Add a new grid\n\t\t\t_appendGrids( data, 'up' );\n\n\t\t\tif( callback_func ) {\n\t\t\t\tif( typeof callback_func == 'function' )\n\t\t\t\t\tcallback_func();\n\t\t\t\telse\n\t\t\t\t\tconsole.error(callback_func+' is not a function');\n\t\t\t}\n\t\t}\n\t\telse {\n\t\t\tthrow new Error('First parameter of addFwGrid(): '+data+' must be Object');\n\t\t}\n\n\t};\n\n});\n"]}
\ No newline at end of file
diff --git a/src/fallwall.js b/src/fallwall.js
index 3f4b4f8..7f2037f 100644
--- a/src/fallwall.js
+++ b/src/fallwall.js
@@ -97,7 +97,7 @@
 	 * Fallwall construtcor
 	 * Setup template and data source
 	 */
-	$.fn.fallwall_init = ( template, dataArray, options, callbackFunction ) => {
+	$.fn.fallwall_init = function( template, dataArray, options, callbackFunction ) {
 
 		/**
 		 * check required parameters