​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>JavaScript 数字</h1>
​
<p>如果数字字符串和数字相加，结果将是级联字符串：</p>
​
<p id="demo"></p>
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<script>
var x = "10";
var y = 20;
document.getElementById("demo").innerHTML = "结果是：" + x + y;
</script>
​
</body>
</html>
​