鼠标效果

<input id="btn1" type="button" value="按 钮" />
<input type="button" value="按 钮" onclick="btn_click()" />
<input type="text" onblur="alert('失去焦点')" />
<select onchange="alert('改变')">
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
</select>
<input type="text" onkeyup="alert('按键抬起')" />
<img src="1.jpg" onmouseleave="alert('鼠标移上')" />

<script>
var btn1 = document.getElementById("btn1");
btn1.onclick = function(){
alert("点击");
}

function btn_click(){
alert("点击");
}


</script>