我在组合 html 和 javascript 时遇到问题,在一种情况下我可以使图像可见,而在另一种情况下我不能。
我有一个工作示例“打开灯”,其中隐藏的图像变得可见 这使得灯泡的图片可见 -
<!DOCTYPE html>
<html>
<body>
<center>
<h1>Switch on the Light</h1>
<img id="light" src="alternateCoolBulb.jpeg" style="width:100px" >
<p>
<input type="button" id="onButton" value="Turn On the Light" />
<p>
</center>
</body>
<script>
function init() {
document.getElementById("light").style.visibility = "hidden";
var onButton = document.getElementById("onButton");
onButton.onclick = function() {
demoVisibility() ;
}
}
function demoVisibility() {
document.getElementById("light").style.visibility = "visible";
}
document.addEventListener('readystatechange', function() {
if (document.readyState === "complete") {
init();
}
});
</script>
</html>
然后我尝试在示例“这只鸟叫什么”中使用相同的想法使灯泡可见。这个例子不能正常工作。
在此示例中,我将灯泡图像放入表格单元格中并将它们设置为隐藏。灯泡是表格单元格内的图像,而该表格单元格位于表单内。
我希望当用户使用单选按钮单击正确答案,然后单击与“OnSubmitForm”关联的“检查答案”按钮时,灯泡可见。
在此示例中,我对信息进行了硬编码,以假设第二个答案是正确答案。
当我点击下面的第二个答案时,灯泡没有出现。我在控制台日志中没有收到任何错误 - 但灯泡不可见。
我想知道是否...
使用有一些不同 并重置可见性属性 - 正如第一个工作示例中所做的那样
并且
更改表单中表格单元格内的图像属性
或者
在第一个工作示例中使用点击有一些不同的工作方式
注意1我能够更改表格内单选按钮的标签,这让我认为我应该能够更改表格内的其他内容
注意2我创建了第三行测试,其中与灯泡图像在同一行中没有单选按钮,并且我尝试在 init 函数中(而不是在 OnSubmitForm 函数中)将灯泡图像从隐藏更改为可见。那也不行。这是显示“在此处打开一盏灯 - 在 Init 函数内...”的单元格
<html>
<center>
What is this bird called?
<p>
<img id = "photo" src="img/testImages/spotted Sandpipler.JPG"
alt="a bird"
height="150" width="100"style="clear: left" />
</center>
<table>
<form name="myform" onsubmit="OnSubmitForm();">
<tr>
<td>
<input type="radio" id = 'first' name="operation" value="1"
> <label for="alsoFirst"> Answer 1 </label>
</td>
<td>
根据建议进行编辑
<img style="visibility: hidden;" id="light1" src="img/alternateCoolBulb.jpeg" height="52" width="42" >
</td>
</tr>
<tr>
<td>
<input type="radio" id = 'second' name="operation" value="2">
<label for="alsoSecond">Answer 2</label>
</td>
<td>
根据建议进行编辑
<img style="visibility: hidden;" id="light2" src="img/alternateCoolBulb.jpeg" height="52" width="42" >
</td>
</tr>
<tr>
<td>
Turn a light on here - Within init function - no use of the check answer button
</td>
<td>
根据建议进行编辑
<img style="visibility: hidden;" id="light3" src="img/alternateCoolBulb.jpeg" height="52" width="42" >
</td>
</tr>
<p>
</p>
</table>
<input type="submit" name="submit" value="Check Answer">
</form>
<script type="text/javascript">
//history
//https://stackoverflow.com/questions/32292962/javascript-how-to-change-radio-button-label-text
//https://stackoverflow.com/questions/37954245/image-will-not-switch-between-hidden-and-show
document.addEventListener('readystatechange', function() {
// Seems like a GOOD PRACTICE - keeps me from getting type error I was getting
// https://stackoverflow.com/questions/14207922/javascript-error-null-is-not-an-object
if (document.readyState === "complete") {
init();
}
});
function init() {
console.log ("Init Function here ");
由于上面的编辑,由这里的人们进行...当我在此初始化函数中放入以下 3 行时,所有灯泡现在都会显示
document.getElementById("light3").style.visibility = "visible";
document.getElementById("light2").style.visibility = "visible";
document.getElementById("light1").style.visibility = "visible";
但是当我注释掉以上 3 行时,无论我将这些行放在 OnSubmitForm 函数中的什么位置,OnSubmitForm 都无法做到同样的事情,尽管它显然是因为警报和 console.log 测试而被调用的
var label = document.getElementsByTagName('label') [0];
label.innerHTML = 'Curlew ';
var label1 = document.getElementsByTagName('label') [1];
label1.innerHTML = 'Sandpiper';
}
function OnSubmitForm()
{
// NONE of the light bulbs display when I put them anywhere in this function
if(document.getElementById('first').checked == true)
{
//alert ( "You have selected the first answer - WRONG" );
console.log( "You have selected the first answer - WRONG" );
document.getElementById("light1").style.visibility = "visible";
}
else
if(document.getElementById('second').checked == true)
{
alert ( "You have selected the SECOND answer - RIGHT" );
// This light bulb does not display - though the alert above is triggered
document.getElementById("light2").style.visibility = "visible";
}
// and for the heck of it I tried making all 3 lights visible here - no go
document.getElementById("light1").style.visibility = "visible";
document.getElementById("light2").style.visibility = "visible";
document.getElementById("light3").style.visibility = "visible";
return false;
}
</script>
</html>
我尝试使用 Make html hidden input visible 中的想法,但我不知道如何使用其中的想法。我测试了第三行如下,但它没有隐藏它。所以这可能是要做的事情,但我不知道如何将其合并
<tr>
<td>
Turn a light on here - Within init function - no use of the check answer button
</td>
<td>
<img type="hidden" id="light3" src="img/alternateCoolBulb.jpeg" height="52" width="42" >
</td>
</tr>
最佳答案
您只需更改该输入类型的可见性即可。 这种鸟叫什么名字?
height="150" width="100"style="clear: left" />
</center>
<table>
<form name="myform" onsubmit="OnSubmitForm();">
<tr>
<td>
<input type="radio" id = 'first' name="operation" value="1"
> <label for="alsoFirst"> Answer 1 </label>
</td>
<td>
<img id="light1" src="img/alternateCoolBulb.jpeg" height="52" width="42" style="visibility: hidden;" >
</td>
</tr>
<tr>
<td>
<input type="radio" id = 'second' name="operation" value="2">
<label for="alsoSecond">Answer 2</label>
</td>
<td>
<img id="light2" src="img/alternateCoolBulb.jpeg" height="52" width="42" style="visibility: hidden;" >
</td>
</tr>
<tr>
<td>
Turn a light on here - Within init function - no use of the check answer button
</td>
<td>
<img style="visibility: hidden;" id="light3" src="img/alternateCoolBulb.jpeg" height="52" width="42" >
</td>
</tr>
<p>
</p>
</table>
<input type="submit" name="submit" value="Check Answer">
</form>
<script type="text/javascript">
//history
//http://stackoverflow.com/questions/32292962/javascript-how-to-change-radio-button-label-text
//http://stackoverflow.com/questions/37954245/image-will-not-switch-between-hidden-and-show
document.addEventListener('readystatechange', function() {
// Seems like a GOOD PRACTICE - keeps me from getting type error I was getting
// http://stackoverflow.com/questions/14207922/javascript-error-null-is-not-an-object
if (document.readyState === "complete") {
init();
}
});
function init() {
console.log ("expect to change -Answer 1- displayed by first button ");
// This light bulb does not display either...
document.getElementById("light3").style.visibility = "visible";
var label = document.getElementsByTagName('label') [0];
label.innerHTML = 'Curlew ';
var label1 = document.getElementsByTagName('label') [1];
label1.innerHTML = 'Sandpiper';
}
function OnSubmitForm()
{
if(document.getElementById('first').checked == true)
{
alert ( "You have selected the first answer - WRONG" );
}
else
if(document.getElementById('second').checked == true)
{
alert ( "You have selected the SECOND answer - RIGHT" );
// This light bulb does not display - though the alert above is triggered
document.getElementById("light2").style.visibility = "visible";
return true;
}
return false;
}
</script>
关于HTML 中的 javascript 如何使隐藏图像在函数调用中可见?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/39738107/