JavaScript if...else 语句-在线运行代码案例-大卫编程网

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<!DOCTYPE html>
<html>
<title>JavaScript if...else 语句示例 - 基础教程(div.cn)</title>
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<body>
<h1>JavaScript if...else 语句</h1>
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<p>单击按钮以显示消息，如果变量x的值小于0，则打印" NEGATIVE"，否则显示" POSITIVE"：</p>
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<button onclick="myFunc()">Demo</button>
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<p id="result"></p>
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<script>
function myFunc() {
   var x = -4;
   var msg;
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   if (x < 0) {
      msg = "NEGATIVE";
   } else {
      msg = "POSITIVE";   
   }
   
document.getElementById("result").innerHTML = msg;
}
</script>
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</body>
</html>