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[英]Javascript from HTML - How to make image visible from submit function? (no CSS)
[英]javascript from HTML How to make hidden image visible within function call?
我在結合html和javascript時遇到問題,在一種情況下,我可以使圖像可見,而在另一種情況下,我不能。
我有一個工作示例,其中隱藏圖像變得可見這使得燈泡的圖片可見“關於燈開關” -
<!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,我嘗試使用相同的想法在示例“這只鳥叫什么”中使燈泡可見。 這個例子行不通。
在此示例中,我將燈泡圖像放在表格單元格中並將其設置為隱藏。 燈泡是表格單元格中的圖像,並且該表格單元格在表單內。
當用戶使用單選按鈕單擊正確的答案,然后單擊與“ OnSubmitForm”關聯的“檢查答案”按鈕時,我想使燈泡可見。
在此示例中,我對信息進行了硬編碼,以假定第二個答案是正確的答案。
當我單擊下面的第二個答案時,燈泡不出現。 我在控制台日志中沒有任何錯誤-但是燈泡不可見。
我懷疑是否...
使用和重置可見性屬性有一些不同-如第一個工作示例所述
和
在表格中更改表格單元格內的圖像屬性
要么
關於在第一個工作示例中使用單擊的方式有所不同
注1: 我能夠改變表內的單選按鈕的標簽,這讓我覺得我應該能在表中更改其他的事情
NOTE2我創建了第三行測試,其中與燈泡圖像同一行中沒有單選按鈕,並且我嘗試在init函數而不是OnSubmitForm函數中將燈泡圖像從隱藏更改為可見。 那也不行。 這是顯示“在此處打開燈-在Init Function中...”的單元格。
<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>
根據建議進行編輯
<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>
根據建議進行編輯
<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>
根據建議進行編輯
<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 ");
由於上面的編輯,是這里的人們所做的...當我在此init函數中放置以下3行時,現在將顯示所有燈泡
document.getElementById("light3").style.visibility = "visible";
document.getElementById("light2").style.visibility = "visible";
document.getElementById("light1").style.visibility = "visible";
但是,當我將以上三行注釋掉時,無論將行放在OnSubmitForm函數中的什么位置,OnSubmitForm都無法做到,盡管顯然是由於警報和console.log測試而調用了該行
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>
我嘗試使用“ 使html隱藏的輸入變為可見”中的想法,但無法弄清楚如何在其中使用這些想法。 我測試了以下第三行,但沒有將其隱藏。 所以這可能是要做的事情,但我不知道如何將其合並
<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>
只是您需要更改該輸入類型的可見性。 這只鳥叫什么名字?
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>
不知道是否知道這一點,但是type =“ hidden”是用於輸入標簽的,而不是img標簽的。 它定義輸入類型,在這種情況下,它為表單而不是樣式提供隱藏的輸入。 你想做什么
<img style="visibility: hidden;" id="light3" src="img/alternateCoolBulb.jpeg" height="52" width="42" >
因此,當您的JavaScript運行時,它實際上會更改標簽樣式的可見性。
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