我正在使用Angular在Ionic 5中开发一个基于点的问题游戏。我之前问过如何使加法按钮按预期工作，效果很好，但现在当尝试使用相同的方法进行点减法时，我得到了一个"Nan"框。
我试图重新设计我的 GUI 以查看问题是否出在那一边，但没有任何变化。
总的来说，我是Ionic和HTML的超级初学者，所以我的代码可能会很垃圾。任何帮助都会很棒！
下面是我进行任何修改之前的代码。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Point Game</title>
<script type="module" src="https://cdn.jsdelivr.net/npm/@ionic/core@4.7.4/dist/ionic/ionic.esm.js"></script>
<script nomodule src="https://cdn.jsdelivr.net/npm/@ionic/core@4.7.4/dist/ionic/ionic.js"></script>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@ionic/core@4.7.4/css/ionic.bundle.css"/>
<style>
:root {
--ion-safe-area-top: 20px;
--ion-safe-area-bottom: 22px;
}
</style>
<script>
function openMenu() {
document.querySelector('ion-menu-controller').open();
}
function p1point(){
var p1pp = document.getElementById("p1p").innerText; //getting text inside element
p1pp = parseInt(p1pp) + 1; //Increment
document.getElementById("p1p").innerHTML = p1pp; // Writing values
}
function p2point(){
var p2pp = document.getElementById("p2p").innerText; //getting text inside element
p2pp = parseInt(p2pp) + 1; //Increment
document.getElementById("p2p").innerHTML = p2pp; // Writing values
}
function p1minus(){
var p1mm = document.getElementById("p1min").innerText; //getting text inside element
p1mm = parseInt(p1mm) - 1; //Increment
document.getElementById("p1min").innerHTML = p1mm; // Writing values
}
function p2minus(){
var p2mm = document.getElementById("p2min").innerText; //getting text inside element
p2mm = parseInt(p2mm) - 1; //Increment
document.getElementById("p2min").innerHTML = p2mm; // Writing values
}
</script>
</head>
<body>
<ion-app>
<ion-menu side="start">
<ion-header>
<ion-toolbar translucent>
<ion-title>Menu</ion-title>
</ion-toolbar>
</ion-header>
<ion-content>
<ion-list>
<ion-item>
<ion-icon name="home" slot="start"></ion-icon>
<ion-label>Home</ion-label>
</ion-item>
<ion-item>
<ion-icon name="person" slot="start"></ion-icon>
<ion-label>Profile</ion-label>
</ion-item>
<ion-item>
<ion-icon name="chatbubbles" slot="start"></ion-icon>
<ion-label>Messages</ion-label>
</ion-item>
<ion-item>
<ion-icon name="settings" slot="start"></ion-icon>
<ion-label>Settings</ion-label>
</ion-item>
</ion-list>
</ion-content>
</ion-menu>
<div class="ion-page" main>
<ion-header>
<ion-toolbar>
<ion-buttons slot="start">
<ion-menu-button></ion-menu-button>
</ion-buttons>
<ion-title>Point Game</ion-title>
</ion-toolbar>
</ion-header>
<ion-content class="ion-padding">
<ion-grid>
<ion-row>
<ion-col>
<ion-card>
<!--Player 1 score-->
<ion-card-header>
<ion-card-subtitle class = "ion-text-center">Player 1</ion-card-subtitle>
<ion-card-title class = "ion-text-center" id = "p1p">0</ion-card-title>
</ion-card-header>
</ion-card>
</ion-col>
<ion-col size = -1>
<!-- fake inner thing psuedo-col-->
</ion-col>
<ion-col>
<ion-card>
<!--Player 2 score-->
<ion-card-header>
<ion-card-subtitle class = "ion-text-center">Player 2</ion-card-subtitle>
<ion-card-title class = "ion-text-center" id = "p2p">0</ion-card-title>
</ion-card-header>
</ion-card>
</ion-col>
</ion-row>
<ion-row>
<ion-col width-50 style = "text-align: right">
<ion-button id = "p1plus" onclick="p1point()" > + </ion-button>
</ion-col>
<ion-col size = .15>
<!-- fake inner thing psuedo-col-->
</ion-col>
<ion-col width-50 style = "text-align: right">
<ion-button id = "p2plus" onclick="p2point()"> + </ion-button>
</ion-col>
<ion-col size = -3>
<!-- fake inner thing psuedo-col-->
</ion-col>
</ion-row>
</ion-row>
<ion-row>
<ion-col width-50 style = "text-align: right">
<ion-button id = "p1min" onclick="p1minus()" > - </ion-button>
</ion-col>
<ion-col size = .15>
<!-- fake inner thing psuedo-col-->
</ion-col>
<ion-col width-50 style = "text-align: right">
<ion-button id = "p2min" onclick="p2minus()"> - </ion-button>
</ion-col>
<ion-col size = -3>
<!-- fake inner thing psuedo-col-->
</ion-col>
</ion-row>
</ion-grid>
</ion-content>
</div>
</ion-app>
<ion-menu-controller></ion-menu-controller>
</body>
</html>
我认为减号函数的问题在于您正在获得按钮的innerText。您使用的是p1min和p2minID，这些文本不是数字。这就是为什么你会得到NaN.