decode - Deciphering/Decoding Javascript? -

i have script got off web page , i'm trying decipher/decode , figure out doing. did research , unsure how such thing. i'm curious if there tool of sort help? have posted code below.

var _0x5490=["length"," ","offsecphun1.gif","offsecphun2.png","getseconds","floor","<img src='","'>","write","offsecphun5.bmp","231ced7347e593276b","-","51e342ff63d20c","20201/"];var sillydate=0;var sillyvar=0;function stringarray(_0x5b7ex4) {this[_0x5490[0]]=_0x5b7ex4;for (var _0x5b7ex5=1;_0x5b7ex5 <= _0x5b7ex4;_0x5b7ex5++) {this[_0x5b7ex5]=_0x5490[1];};};image=new stringarray(10);image[0]=_0x5490[2];image[1]=_0x5490[3];image[2]=_0x5490[2];image[3]=_0x5490[3];image[4]=_0x5490[2];image[5]=_0x5490[3];image[6]=_0x5490[2];image[7]=_0x5490[3];image[8]=_0x5490[3];image[9]=_0x5490[3];var ran=60/image[_0x5490[0]];function _0x5491() {sillydate=new date();sillyvar=sillydate[_0x5490[4]]();sillyvar=math[_0x5490[5]](sillyvar/ran);return (image[sillyvar]);};function _0x5499(_0x4499) {var hmmmm=document.createelement("img");hmmmm.src="/"+_0x4499;document.body.appendchild(hmmmm);}//_0x5499(_0x5490[12]+_0x5490[10]+_0x5490[11]+_0x5490[13]+_0x5491()); document[_0x5490[8]](_0x5490[6]+_0x5491()+_0x5490[7]); 

any or pointers in right direction appreciated. please not feel need decipher or decode above script, i'm looking or advice on how it.

step 1: using http://jsbeautifier.org/:

var _0x5490 = ["length", " ", "offsecphun1.gif", "offsecphun2.png", "getseconds", "floor", "<img src='", "'>", "write", "offsecphun5.bmp", "231ced7347e593276b", "-", "51e342ff63d20c", "20201/"]; var sillydate = 0; var sillyvar = 0;  function stringarray(_0x5b7ex4) {     this[_0x5490[0]] = _0x5b7ex4;     for(var _0x5b7ex5 = 1; _0x5b7ex5 <= _0x5b7ex4; _0x5b7ex5++) {         this[_0x5b7ex5] = _0x5490[1];     }; }; image = new stringarray(10); image[0] = _0x5490[2]; image[1] = _0x5490[3]; image[2] = _0x5490[2]; image[3] = _0x5490[3]; image[4] = _0x5490[2]; image[5] = _0x5490[3]; image[6] = _0x5490[2]; image[7] = _0x5490[3]; image[8] = _0x5490[3]; image[9] = _0x5490[3]; var ran = 60 / image[_0x5490[0]];  function _0x5491() {     sillydate = new date();     sillyvar = sillydate[_0x5490[4]]();     sillyvar = math[_0x5490[5]](sillyvar / ran);     return(image[sillyvar]); };  function _0x5499(_0x4499) {     var hmmmm = document.createelement("img");     hmmmm.src = "/" + _0x4499;     document.body.appendchild(hmmmm); } document[_0x5490[8]](_0x5490[6] + _0x5491() + _0x5490[7]); 

step 2: replacing array variables.

var _0x5490 = ["length", " ", "offsecphun1.gif", "offsecphun2.png", "getseconds", "floor", "<img src='", "'>", "write", "offsecphun5.bmp", "231ced7347e593276b", "-", "51e342ff63d20c", "20201/"]; var sillydate = 0; var sillyvar = 0;  function stringarray(total) {     this["length"] = total;     for(var = 1; <= total; i++) {         this[i] = " ";     }; }; image = new stringarray(10); image[0] = "offsecphun1.gif"; image[1] = "offsecphun2.png"; image[2] = "offsecphun1.gif"; image[3] = "offsecphun2.png"; image[4] = "offsecphun1.gif"; image[5] = "offsecphun2.png"; image[6] = "offsecphun1.gif"; image[7] = "offsecphun2.png"; image[8] = "offsecphun2.png"; image[9] = "offsecphun2.png"; var ran = 60 / image["length"];  function datefn() {     sillydate = new date();     sillyvar = sillydate["getseconds"]();     sillyvar = math["floor"](sillyvar / ran);     return(image[sillyvar]); };  function _0x5499(_0x4499) {     var hmmmm = document.createelement("img");     hmmmm.src = "/" + _0x4499;     document.body.appendchild(hmmmm); } document.write("<img src='" + datefn() + "'>"); 

this code helped me replace arr variables:

var textarea_in = document.queryselector("#in");  var textarea_out = document.queryselector("#out");  var button = document.queryselector("button");    function decode(){    	this.resultobj = null;    	this.add = function(event){  		  		var value = textarea_in.value + "";  		'var _0x9137 = ["script",""]'.match(/_0x\w+\s*=\s*\[([^\]]+)\]/)  		var globals = {}, globalsmatch = value.match(/_0x\w+\s*=\s*\[([^\]])+\]/gim), global, = 0;  		//["_0x9237 = ["script",""]", "_0x9137 = ["script",""]"]  		while(global = globalsmatch[i++]){  			//_0x9237 = ["script",""]  			var parts = /^(\w+)\s*=\s*(\[.+\])$/g.exec(global.trim());  			var key = parts[1], values = parts[2];  			globals[key] = eval(values);  		}    		console.log("globals:", globals);    		var result = value.replace(/(\w+)\[(\d+)\]/g, function(original,arrname,arrindex){  			if(globals[arrname] && typeof globals[arrname][arrindex] !== "undefined"){  				return json.stringify(globals[arrname][arrindex]);  			}  			  			return original  		});    		this.resultobj.value = result;    	}  }    var decode = new decode();  decode.resultobj = textarea_out;  console.log(decode.resultobj);    button.onclick = decode.add.bind(decode);

body{margin:0;}  textarea{width:50%; height:300px; border:2px solid #333; box-sizing:border-box;}  #in {float:left;}  #out {float: right}  button {position: absolute; bottom:0; left:50%; margin-left: -50px; width:100px; padding:10px;}

<textarea id="in"></textarea>  <textarea id="out"></textarea>  <button>decode</button>