Dictionary(ja<->en) for Safari #save this html-file to your local disk.

gistfile1.html

<meta http-equiv="content-type" content="charset=utf-8">
<title>dictionary</title>
<script>
var http;
var lang=["en","ja"];
var url="http://translate.google.co.jp/translate_a/t?client=t";
function $(id){return document.getElementById(id);}
function getText(){
	return $("text").value.split("\n").join(" ");
}

function getLang(text){
	for(var i=0;i<text.length;i++){
		if(text.charCodeAt(i)>128)return ["ja","en"]
	}
	return ["en","ja"];
}
function abort(){if(http){http.abort();http=null;}}
function loadData(){
	var text=getText();
	if(!text)return;
	if(http&&http.text==text)return;
	abort();
	var data=getCache(text);
	if(data){show(data);return;}
	http=new XMLHttpRequest();http.text=text;
	
	
	var lang=getLang(text);
	http.open("GET",url+"&sl="+lang[0]+"&tl="+lang[1]+"&text="+encodeURIComponent(text),true);
	http.onreadystatechange=cbFunc;
	http.send(null);
	setloading(true);
}
var timer=0;
function load(){
	clearTimeout(timer);
	var text=getText();
	if(text==""){show(null);return;}
	var data=getCache(text);
	if(data){abort();show(data);return;}
	timer=setTimeout(loadData,200);
}

function cbFunc(){
	if(!http||http.readyState!=4)return;
	setloading(false);
	var value=http.responseText;
	var status=http.status;
	var text=http.text;
	http=null;
	if(status!=200){$("sentence").innerHTML=$("dict").innerHTML="error";return;}
	try{
		var data=eval("("+value+")");
		addCache(text,value);
		show(data);
	}catch(e){}
}

var loadingtimer=0,loadingcnt=0;
function loadingfunc(){
	$("loading").style.opacity=0.4+0.2*Math.cos(loadingcnt++/10);
}
function setloading(flag){
	if(flag){
		loadingcnt=0;
		loadingtimer=setInterval(loadingfunc,10);
	}else{
		clearInterval(loadingtimer);
		$("loading").style.opacity=0;
	}
}
function htmlchars(str){
	return str.split("&").join("&amp;").split("<").join("&lt;").split(">").join("&gt;").split(" ").join("&nbsp;").split("\n").join("<br>");
}
function show(data){
	$("sentence").innerHTML=$("dict").innerHTML="";
	if(data==null)return;
	var st=data[0];
	var dict=data[1];
	if(st&&st[0]&&st[0][0]){
		$("sentence").innerHTML+="<h3>翻訳</h3>";
		$("sentence").innerHTML+=htmlchars(st[0][0])+"<br>";
	}
	if(dict&&dict.length>0){
		$("dict").innerHTML+="<h3>辞書</h3>";
		for(var i=0;i<dict.length;i++){
			$("dict").innerHTML+="<h4>"+dict[i][0]+"</h4>"
			$("dict").innerHTML+=htmlchars(dict[i][1].join("  "));
		}
	}
}
function info(){
	var text="Cache-size: "+cachedata.list_length+"/"+cachedata.MAX_LEN+"\n";
	text+="--recent words--\n--------------------------------\n";
	for(var i=0,o=cachedata.list_tail;o&&i<20;i++,o=o.prev){
		text+=o.key+"\n--------------------------------\n";
	}
	alert(text);
}
var cachedata={MAX_LEN:4096,list_length:0,list_head:null,list_tail:null,map:{}};
function getCache(key){
	var node=cachedata.map[key];
	if(!node)return null;
	if(node.next){
		if(!node.prev){
			cachedata.list_head=node.next;
			node.next.prev=null;
		}else{
			node.prev.next=node.next;
			node.next.prev=node.prev;
		}
		node.next=null;
		node.prev=cachedata.list_tail;
		node.prev.next=node;
		cachedata.list_tail=node;
	}
	return eval("("+node.value+")");
}
function addCache(key,value){
	if(getCache(key))return;
	var node={key:key,value:value};
	cachedata.map[key]=node;
	if(cachedata.list_length==0){
		cachedata.list_head=cachedata.list_tail=node;
		cachedata.list_length=1;
		return;
	}
	node.prev=cachedata.list_tail;
	cachedata.list_tail.next=node;
	cachedata.list_tail=node;
	cachedata.list_length++;
	if(cachedata.list_length>cachedata.MAX_LEN){
		cachedata.list_length=cachedata.MAX_LEN;
		delete cachedata.map[cachedata.list_head.key];
		cachedata.list_head=cachedata.list_head.next;
		cachedata.list_head.prev=null;
	}
}
function escapeBS(str){return str.split("\\").join("\\\\").split("\n").join("\\n");}
function unescapeBS(str){return str.split("\\\\").join("\\").split("\\n").join("\n");}
function onload(){
	$('text').focus();
	window.onunload=onexit;
	var dict=[];
	try{dict=JSON.parse(localStorage.dictionary);}catch(e){console.log(e);}
	for(var i=0;i<dict.length;i++)addCache(dict[i][0],dict[i][1])
}
function onexit(){
	var data=[];
	for(var obj=cachedata.list_head;obj;obj=obj.next){
		data.push([obj.key,obj.value]);
	}
	console.log(data);
	localStorage.dictionary=JSON.stringify(data);
	return false;
}
</script>
<style>
body{font-size:24px;}
#text{width:100%;background:#dde;font-size:32px;border:none;outline:none;font-family:Serif;resize:none}
h3{background:#ddf;padding;0;margin:4px 0;font-size:32px;}
h4{background:#ddf;padding;0;margin:0 0;font-size:28px;}
#loading{font-size:16px;color:gray;}
form{display:inline}

</style>
<body onload="onload();" onkeypress="if(event.metaKey&&event.keyCode==105){info();return false;}">
<form onsubmit="load();return false;">
<textarea type=text oninput="setTimeout(load,0)" id="text"></textarea>
</form>
<span id="loading" style="opacity:0">loading...</span>
<div id="sentence"></div>
<br>
<div id="dict"></div>