<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>JS基础——if else语句和innerHTML的使用</title>
<style>
#div1{ width:260px; height:200px; border:1px solid #ccc; background:#f4f4f4;}
</style>
<script>
window.onload = function(){
	var oDiv = document.getElementById('div1');
	var oStrong = document.getElementById('strong1');
	var oText = document.getElementById('text1');
	var oBtn = document.getElementById('btn1');
	
	oBtn.onclick = function(){
		if(oText.value == ''){
			alert('亲,说点什么吧~~');
		}else{
			oDiv.innerHTML = oStrong.innerHTML + oText.value +'<br/>' + oDiv.innerHTML;
			oText.value = '';
		}	
	};	
};
</script>
</head>

<body>
<div id="div1"></div>
<strong id="strong1">张三:</strong>
<input id="text1" type="text" />
<input id="btn1" type="button" value="提交" />
</body>
</html>