<html>
<body>
<p>点击按钮创建及增加字符串变量。</p>
<button onclick="myFunction()">点击这里</button>
<p id="demo"></p>
<script>
function myFunction()
{
var x=5+5;
var y="5"+5;
var z="Hello"+5;
var demoP=document.getElementById("demo");
demoP.innerHTML=x + "<br>" + y + "<br>" + z;
}
</script>
</body>
</html>