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JavaScript ?? - ???, ????, ??

JavaScript ?? - throw, try ? catch

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JavaScript ??

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JavaScript?? ??? ?????

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JavaScript try ? catch

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JavaScript ?? try? catch? ??? ?????.

Syntax

try {
//在這里運(yùn)行代碼
}catch(err){
//在這里處理錯(cuò)誤}

Examples

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<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <script> function myFunction(){ try{ var x=document.getElementById("demo").value; if(x=="") throw "值為空"; if(isNaN(x)) throw "不是數(shù)字"; if(x>10) throw "太大"; if(x<5) throw "太小"; } catch(err){ var y=document.getElementById("mess"); y.innerHTML="錯(cuò)誤：" + err + "。"; } } </script> </head> <body> <h1>我的第一個(gè) JavaScript</h1> <p>請(qǐng)輸出一個(gè) 5 到 10 之間的數(shù)字:</p> <input id="demo" type="text"> <button type="button" onclick="myFunction()">測(cè)試輸入</button> <p id="mess"></p> </body> </html>