if else javascript 错误

Question

我正在尝试编写一个简单的代码，这样当您插入您的姓名时，它会将其插入到文本中，但如果您不插入您的姓名，它会要求您插入您的姓名。该代码似乎应该可以工作，但事实并非如此。谁能帮帮我？

<body>

<h3>Please enter your name</h3>

<input type="text" id="name" value="" placeholder="Please enter your name">

<p id="dolly"></p>

<button onclick="yourName()">Enter</button>


<script>
function yourName() {
var x = document.getElementById("name").value;
if (x == "") {
document.getElementById("dolly").innerHTML = "Hello, " + x + ", My name is Dolly.";
} else {
document.getElementById("dolly").innerHTML = "Please enter your name.";
}
</script>
</body>

Answer 1

function yourName() {
var x = document.getElementById("name").value;
if (x.length != 0) {
document.getElementById("dolly").innerHTML = "Hello, " + x + ", My name is Dolly.";
} else {
document.getElementById("dolly").innerHTML = "Please enter your name.";
}
}

Answer 2

将if (x == "")更改为if (x != "")并关闭函数大括号。

<body>

<h3>Please enter your name</h3>

<input type="text" id="name" value="" placeholder="Please enter your name">

<p id="dolly"></p>

<button onclick="yourName()">Enter</button>


<script>
function yourName() {
  var x = document.getElementById("name").value;
  if (x != "") {
    document.getElementById("dolly").innerHTML = "Hello, " + x + ", My name is Dolly.";
  } else {
    document.getElementById("dolly").innerHTML = "Please enter your name.";
  }
}
</script>
</body>

Answer 3

将 if(x=="") 更改为 if(x!=="" && x.length!==0) 并添加右大括号以关闭函数。完整代码如下

<body>

<h3>Please enter your name</h3>

<input type="text" id="name" value="" placeholder="Please enter your name">

<p id="dolly"></p>

<button onclick="yourName()">Enter</button>


<script>
function yourName() {
  var x = document.getElementById("name").value;
  if (x !== "" && x.length !==0) {
    document.getElementById("dolly").innerHTML = "Hello, " + x + ", My name is Dolly.";
  } else {
    document.getElementById("dolly").innerHTML = "Please enter your name.";
  }
}
</script>
</body>

if else javascript 错误

If else javascript error

html

javascript

if-statement

var

function