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<!DOCTYPE html> <html> <body> <h1>JavaScript 数字</h1> <p>如果数字和数字字符串相加，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>