Selenium1.0时代就是用javascript实现的，应该用了类似手段。
<html>
<head>
<title>
发送模拟按键
</title>
</head>
<body>
<div id="mydiv">点击按钮向文字框发送模拟按键（仅对firefox有效）
<textarea id="myTextbox" name="yes"></textarea>
</div>
<form name="myform" method="get">
<input type="button" id="mybtn" value="click me">
</form>
<script type="text/javascript">
var btn=document.getElementById("mydiv");
var btn=document.getElementById("mybtn");
var textbox=document.getElementById("myTextbox");
var evt;
if(document.implementation.hasFeature("KeyboardEvents","3.0")){
evt=document.createEvent("KeyEvents");
}
mydiv.onclick=function(){
textbox.value="";
}
textbox.onkeydown=function(event){
textbox.value=textbox.value+String.fromCharCode(evt.which);
}
btn.onclick=function(){
evt.initKeyEvent("keydown",false,true,document.defaultView,false,false,false,false,97,97);
textbox.dispatchEvent(evt);
evt.initKeyEvent("keydown",false,true,document.defaultView,false,false,false,false,100,100);
textbox.dispatchEvent(evt);
evt.initKeyEvent("keydown",false,true,document.defaultView,false,false,false,false,109,109);
textbox.dispatchEvent(evt);
evt.initKeyEvent("keydown",false,true,document.defaultView,false,false,false,false,105,105);
textbox.dispatchEvent(evt);
evt.initKeyEvent("keydown",false,true,document.defaultView,false,false,false,false,110,110);
textbox.dispatchEvent(evt);
}
</script>
</body>
</html>
