我正在尝试制作一个仅包含图像和
的复选框列表表单我有来自add an image to a html type input check box or radio的代码：
<html>
<script type="text/javascript">
//global variables that can be used by ALL the function son this page.
var inputs;
var imgFalse = '52 0 ROff.png';
var imgTrue = '52 0 ROn.png';
//replace the checkbox with an image and setup events to handle it
function replaceChecks() {
//get all the input fields on the page
inputs = document.getElementsByTagName('input');
//cycle trough the input fields
for(var i=0; i<inputs.length; i++) {
//check if the input is a checkbox
if(inputs[i].getAttribute('type') == 'checkbox') {
//create a new image
var img = document.createElement('img');
//check if the checkbox is checked
if(inputs[i].checked) {
img.src = imgTrue;
} else {
img.src = imgFalse;
}
//set image ID and onclick action
img.id = 'checkImage'+i;
//set image
img.onclick = new Function('checkClick('+i+')');
//place image in front of the checkbox
inputs[i].parentNode.insertBefore(img, inputs[i]);
//hide the checkbox
inputs[i].style.display='none';
}
}
}
//change the checkbox status and the replacement image
function checkClick(i) {
if(inputs[i].checked) {
inputs[i].checked = '';
document.getElementById('checkImage'+i).src=getImageUnchecked(i);
} else {
inputs[i].checked = 'checked';
document.getElementById('checkImage'+i).src=getImageChecked(i);
}
}
function getImageChecked(input) {
if (input == 0)
return "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.jpg";
if (input == 1)
return "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.jpg";
}
function getImageUnchecked(input) {
if (input == 0)
return "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.png";
if (input == 1)
return "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.png";
}
function startImages() {
}
</script>
</html>
<head>
</head>
<body>
<input type="checkbox" id="option1" checked/> Test<br>
<input type="checkbox" id="option2" checked/> two<br>
<button onclick="alert('option 1 is checked? ' + document.getElementById('option1').checked
+ 'option 2 is checked? ' + document.getElementById('option2').checked)">Check</button>
<script type="text/javascript">replaceChecks();</script>
</body>
但是图像只在第一次点击后才开始显示。 我是否可以从页面加载开始做任何工作？ 我尝试了现有的功能但没有做任何事情。
答案 0 :(得分：2)
您已将checkClick()附加到图片的点击事件，但您最初从未实际加载图片，因此您必须从for循环调用checkClick(i)。
<html>
<script type="text/javascript">
//global variables that can be used by ALL the function son this page.
var inputs;
var imgFalse = '52 0 ROff.png';
var imgTrue = '52 0 ROn.png';
//replace the checkbox with an image and setup events to handle it
function replaceChecks() {
//get all the input fields on the page
inputs = document.getElementsByTagName('input');
//cycle trough the input fields
for(var i=0; i<inputs.length; i++) {
//check if the input is a checkbox
if(inputs[i].getAttribute('type') == 'checkbox') {
//create a new image
var img = document.createElement('img');
//check if the checkbox is checked
if(inputs[i].checked) {
img.src = imgTrue;
} else {
img.src = imgFalse;
}
//set image ID and onclick action
img.id = 'checkImage'+i;
//set image
img.onclick = new Function('checkClick('+i+')');
//place image in front of the checkbox
inputs[i].parentNode.insertBefore(img, inputs[i]);
//hide the checkbox
inputs[i].style.display='none';
checkClick(i);
}
}
}
//change the checkbox status and the replacement image
function checkClick(i) {
if(inputs[i].checked) {
inputs[i].checked = '';
document.getElementById('checkImage'+i).src=getImageUnchecked(i);
} else {
inputs[i].checked = 'checked';
document.getElementById('checkImage'+i).src=getImageChecked(i);
}
}
function getImageChecked(input) {
if (input == 0)
return "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.jpg";
if (input == 1)
return "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.jpg";
}
function getImageUnchecked(input) {
if (input == 0)
return "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.png";
if (input == 1)
return "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.png";
}
function startImages() {
}
</script>
</html>
<head>
</head>
<body>
<input type="checkbox" id="option1" checked/> Test<br>
<input type="checkbox" id="option2" checked/> two<br>
<button onclick="alert('option 1 is checked? ' + document.getElementById('option1').checked
+ 'option 2 is checked? ' + document.getElementById('option2').checked)">Check</button>
<script type="text/javascript">replaceChecks();</script>
</body>
答案 1 :(得分：1)
您有大量不必要的代码，并且将初始图像值设置为不存在的图像。
此外，您的HTML无效（<html>结束标记必须是文档中的最后一个内容。
此外，you should not use inline HTML event attributes（onclick等）将您的JavaScript与HTML完全分开，并遵循基于标准的现代编码实践。
此外，除非您希望在某些时候（非常不可能）将HTML解析为XML，否则可以省略元素中的最后一个斜杠（<input ... />可以只是<input ... >）。同样，您不再需要在脚本标记中指定type="text/javascript"。
以下是代码的清理和现代化工作版本。注意实际上有多少代码（没有注释，它的代码真的很少）以及代码的简单程度。请查看代码中的注释，了解正在执行的操作和原因。
.hidden { display:none; }<html>
<head>
<title>Checkbox and Images</title>
</head>
<body>
<input type="checkbox" id="option1" checked> Test<br>
<input type="checkbox" id="option2" checked> two<br>
<button id="btnOutput">Check</button>
<script>
// You should never make global variables as they can collide with other variables
// Instead, create a "scope" of your own to work in with an Immediately Invoked
// function expression (an unnamed function that invokes itself right after being
// declared)
(function(){
// Anything declared inside this function is not accessible outside of it
// Since we know these are the only two image paths needed, we can set them up as
// variables and completely do away with the extra functions that set them.
var imgFalse = "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.png";
var imgTrue = "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.jpg";
// Get references to all the DOM elements you will need and then you don't
// have to scan for them again over and over.
var btnOutput = document.getElementById("btnOutput");
// .getElementsByTagName() returns a "live node" list that causes the DOM
// to be re-scanned for the elements everytime you reference the list.
// Use .querySelectorAll() for better efficiency and turn the node list that
// returns into a proper JavaScript array so that .forEach() can be used to
// iterate the elements later.
var checkboxes =
Array.prototype.slice.call(document.querySelectorAll('input[type="checkbox"]'));
// Set up the click event handling function for the button
btnOutput.addEventListener("click", function(){
alert('option 1 is checked? ' + checkboxes[0].checked +
'option 2 is checked? ' + checkboxes[1].checked);
});
// Loop through the checkboxes array
checkboxes.forEach(function(checkbox, index){
// No need to test the input type because this array only contains checkboxes
// create a new image
var img = document.createElement('img');
// Show the right image based on the checked status of the clicked checkbox
if(checkbox.checked) {
img.src = imgTrue;
} else {
img.src = imgFalse;
}
img.id = 'checkImage' + index; // set image ID
img.checked = false;
// Set up image click event handler
img.addEventListener("click", function(){
// Toggle the checked state of the image.
// In JavaScript, the "checked" property is boolean. It has values of true and false,
// not "checked" and "" (those are the values to use in HTML attributes).
this.checked = !this.checked;
if(this.checked) {
img.src= "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.png";
} else {
img.src= "https://azooree.com/wp-content/uploads/2017/08/Logomakr_6HaICv.jpg";
}
});
// place image just prior to the checkbox in the DOM
checkbox.parentNode.insertBefore(img, checkbox);
// Hide the checkbox. Use CSS classes instead of inline styles
checkbox.classList.add("hidden");
});
})();
</script>
</body>
</html>