通过javascript获取表单字段数据抛出错误（值为null）
function myFunc() {
console.log("entered");
document.write('Submitted Data');
var firstname = document.getElementById("fname").value;
var lastname = document.getElementById("lname").value;
document.writeln("Your full name is:" + firstname + lastname);
}
<form>
<label> Firstname </label>
<input type="text" name="firstname" id="fname" size="15" /> <br> <br>
<label> Lastname</label>
<input type="text" name="lastname" id="lname" size="15" /> <br> <br>
<label>
Gender :
</label><br>
<input type="radio" name="male" /> Male <br>
<input type="radio" name="female" /> Female
<br>
<br>
<input type="button" value="Submit" onclick="myFunc()" />
</form>
单击提交后，它不会获取名字并在控制台中显示错误值 null。有人可以帮忙吗？整个代码保存在一个 HTML 页面中
长风秋雁浏览 150回答 1
1回答
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月关宝盒
那是因为这条线document.write('Submitted Data');。document.write删除现有的 html，以便在您使用的下一行中document.getELementById找不到 dom 元素function myFunc() { var firstname = document.getElementById("fname").value; var lastname = document.getElementById("lname").value; document.writeln("Your full name is:" + firstname + lastname);}<body bgcolor="Lightskyblue"> <br> <br> <form> <label> Firstname </label> <input type="text" name="firstname" id="fname" size="15" /> <br> <br> <label> Lastname</label> <input type="text" name="lastname" id="lname" size="15" /> <br> <br> <label> Gender : </label><br> <input type="radio" name="male" /> Male <br> <input type="radio" name="female" /> Female <br> <br> <input type="button" value="Submit" onclick="myFunc()" /> </form></body>
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JavaScript