改变颜色

index.html

@@ -82,7 +82,7 @@ <h3>添加几个按钮/开关 并在后面添加随机数字 ----李岳烁 23.11
     <button onclick="addone('num1')" class="nes-btn is-primary" value="一个按钮" name="button1"
         style="width: 160px;">+1</button>
     <input type="textbox" id="num1" value=><br>
-    <button class="nes-btn is-success" value="另一个按钮" name="button2" style="width: 160px;">改变颜色</button>
+    <button onclick="changecolor()" class="nes-btn is-success"value="另一个按钮" name="button2" style="width: 160px;">改变颜色</button>
     <input type="textbox" id="num2" value=><br>
     <button class="nes-btn is-error" value="最后一个按钮" name="button3" style="width: 160px;">切换正负</button>
     <input type="textbox" id="num3" value=>

test1.js

@@ -2,4 +2,13 @@ function addone(id) {
     var elem = document.getElementById(id);
     var presnt = parseInt(elem.value) || 0;
     elem.value = presnt + 1;
-}
+}
+function changecolor() {
+    let button = document.getElementById("num2"); // access the button by id
+    let color = button.style.color;
+    if (color == "red") { // if button color is red change it green otherwise change it to red.
+       button.style.color = 'green';
+    } else {
+       button.style.color = 'red';
+    }
+ }