<p> + 号运算符用于连接字符串。</p>
<button onclick="myFunction()">点我</button>
<p id="demo"></p>
<script>
function myFunction() {
var text1 = "Good ";
var text2 = "Morning";
var text3 = text1 + text2;
document.getElementById("demo").innerHTML = text3;
}
</script>