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Javascript事件监听器只能运行一次

[英]Javascript Event Listener only works one time

我无法理解为什么以下代码只能运行一次。 任何帮助将非常感激。 现在被困在这里一个了:

 const button = document.querySelector("#myBtn"); var clickCount = 0; function myFunction() { clickCount++; document.body.innerHTML += "<br><br>Button was clicked " + clickCount + " time(s)"; console.log("Button was clicked " + clickCount + " time(s)"); } button.addEventListener("click", myFunction, false); 
 <!DOCTYPE html> <html> <body> <head><script src="script.js" defer></script></head> <button id="myBtn">Try it</button> </body> </html> 

提前致谢!!

来自@nnnnnnn,

不要使用body.innerHTML + = ...添加元素,因为这会覆盖整个现有主体,并实际上会重新创建DOM

您可以在您的正文中添加一个新的div,例如<div id="msg"></div> ,以显示按钮单击事件消息。

 const button = document.querySelector("#myBtn"); var clickCount = 0; function myFunction() { clickCount++; document.getElementById('msg').innerHTML += "<br><br>Button was clicked " + clickCount + " time(s)"; console.log("Button was clicked " + clickCount + " time(s)"); } button.addEventListener("click", myFunction, false); 
 <!DOCTYPE html> <html> <body> <head><script src="script.js" defer></script></head> <button id="myBtn">Try it</button> <div id="msg"></div> </body> </html> 

您正在通过body.innerHTML +=body.innerHTML +=附加的侦听器。 您可以尝试采取以下预防措施:

document.body.insertAdjacentHTML('beforeend', "<br><br>Button was clicked " + clickCount + " time(s)");

insertAdjacentHTML快速可靠。

您也可以尝试appendChild但这将意味着您要附加HTMLElement

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