W3School TIY Editor
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<!DOCTYPE html> <html> <body> <p>请输入 5 到 10 之间的数字：</p> <input id="demo" type="text"> <button type="button" onclick="myFunction()">检测输入</button> <p id="p01"></p> <script> function myFunction() { var message, x; message = document.getElementById("p01"); message.innerHTML = ""; x = document.getElementById("demo").value; try { if(x == "") throw "是空的"; if(isNaN(x)) throw "不是数字"; x = Number(x); if(x < 5) throw "太小"; if(x > 10) throw "太大"; } catch(err) { message.innerHTML = "输入：" + err; } } </script> </body> </html>