我正在尝试选择并返回一些项目(复选框)。一切都很好,但第一项总是显示未定义。无法解决这个问题!
我的代码如下
function checkList () {
var checked;
var i;
for( i = 0; i < document.form1.length; i++) {
var element = document.form1[i]
if (element.type == "checkbox"){
if (element.checked == true){
checked = checked + element.value + "<br/>";
}
}
}
document.getElementById('checked').innerHTML = checked;
}
<form name="form1">
<input type="checkbox" name="checkbox1" id="checkbox1" value="Pen" />
<label value="Earned" for="checkbox1">Pen</label>
<br />
<input type="checkbox" name="checkbox2" id="checkbox2" value="Book" />
<label value="Earned" for="checkbox2" >Book</label>
<br/>
<input type="checkbox" name="checkbox1" id="checkbox3" value="Sharpner" />
<label value="Earned" for="checkbox3">Sharpner</label>
<br/>
<input type="checkbox" id="checkbox4" name="checkbox1" value="Pencil" />
<label value="Earned" for="checkbox4">Pencil</label>
<br/> <br/>
<input type="button" id="done" value="Done" onclick="checkList()" />
<br/><br/>
</form>
<p >You are taking:</p>
<span id="checked"></span>
最佳答案
尝试改变
<form name="form1">
<input type="checkbox" name="checkbox1" id="checkbox1" value="Pen" />
<label value="Earned" for="checkbox1">Pen</label>
<br />
<input type="checkbox" name="checkbox2" id="checkbox2" value="Book" />
<label value="Earned" for="checkbox2" for="checkbox">Book</label>
<br/>
<input type="checkbox" name="checkbox1" id="checkbox3" value="Sharpner" />
<label value="Earned" for="checkbox3" for="checkbox" for="checkbox">Sharpner</label>
<br/>
<input type="checkbox" id="checkbox4" name="checkbox1" value="Pencil" />
<label value="Earned" for="checkbox4">Pencil</label>
<br/> <br/>
<input type="button" id="done" value="Done" onclick="checkList()" />
<br/><br/>
</form>
<p >You are taking:</p>
<span id="checked"></span>
到此....
<form name="form1">
<input type="checkbox" name="checkbox1" id="checkbox1" value="Pen" />
<label value="Earned" for="checkbox1">Pen</label>
<br />
<input type="checkbox" name="checkbox2" id="checkbox2" value="Book" />
<label value="Earned" for="checkbox2">Book</label>
<br/>
<input type="checkbox" name="checkbox3" id="checkbox3" value="Sharpner" />
<label value="Earned" for="checkbox">Sharpner</label>
<br/>
<input type="checkbox" id="checkbox4" name="checkbox4" value="Pencil" />
<label value="Earned" for="checkbox4">Pencil</label>
<br/> <br/>
<input type="button" id="done" value="Done" onclick="checkList()" />
<br/><br/>
</form>
<p >You are taking:</p>
<span id="checked"></span>
代码中有多个重复项,例如 (for="")
请告诉我,谢谢
关于javascript - 复选框(javascript)选择,第一项显示未定义?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30730253/