​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>JavaScript 数字</h1>
​
<p>如果添加两个数字字符串，结果将是级联字符串：</p>
​
<p id="demo"></p>
​
<script>
var x = "10";
var y = "20";
var z = x + y;
document.getElementById("demo").innerHTML = z;
</script>
​
</body>
</html>
​