我一直在编辑这个JS image compare示例，一切都很棒。我只是不知道如何改变一件事。
当向左或向右拉动时，指示用户拖动图像的位置的圆形按钮会从容器中溢出。我在说这个：https://prnt.sc/ja1r6g
如何解决这个问题并将其设置为当它一直向右或向左拉动时，它会在图像下方显示并且不会显示溢出？
这是剪辑的代码：
function initComparisons() {
var x, i;
/*find all elements with an "overlay" class:*/
x = document.getElementsByClassName("img-comp-overlay");
for (i = 0; i < x.length; i++) {
/*once for each "overlay" element:
pass the "overlay" element as a parameter when executing the compareImages function:*/
compareImages(x[i]);
}
function compareImages(img) {
var slider, img, clicked = 0, w, h;
/*get the width and height of the img element*/
w = img.offsetWidth;
h = img.offsetHeight;
/*set the width of the img element to 50%:*/
img.style.width = (w / 2) + "px";
/*create slider:*/
slider = document.createElement("DIV");
slider.setAttribute("class", "img-comp-slider");
/*insert slider*/
img.parentElement.insertBefore(slider, img);
/*position the slider in the middle:*/
slider.style.top = (h / 2) - (slider.offsetHeight / 2) + "px";
slider.style.left = (w / 2) - (slider.offsetWidth / 2) + "px";
/*execute a function when the mouse button is pressed:*/
slider.addEventListener("mousedown", slideReady);
/*and another function when the mouse button is released:*/
window.addEventListener("mouseup", slideFinish);
/*or touched (for touch screens:*/
slider.addEventListener("touchstart", slideReady);
/*and released (for touch screens:*/
window.addEventListener("touchstop", slideFinish);
function slideReady(e) {
/*prevent any other actions that may occur when moving over the image:*/
e.preventDefault();
/*the slider is now clicked and ready to move:*/
clicked = 1;
/*execute a function when the slider is moved:*/
window.addEventListener("mousemove", slideMove);
window.addEventListener("touchmove", slideMove);
}
function slideFinish() {
/*the slider is no longer clicked:*/
clicked = 0;
}
function slideMove(e) {
var pos;
/*if the slider is no longer clicked, exit this function:*/
if (clicked == 0) return false;
/*get the cursor's x position:*/
pos = getCursorPos(e)
/*prevent the slider from being positioned outside the image:*/
if (pos < 0) pos = 0;
if (pos > w) pos = w;
/*execute a function that will resize the overlay image according to the cursor:*/
slide(pos);
}
function getCursorPos(e) {
var a, x = 0;
e = e || window.event;
/*get the x positions of the image:*/
a = img.getBoundingClientRect();
/*calculate the cursor's x coordinate, relative to the image:*/
x = e.pageX - a.left;
/*consider any page scrolling:*/
x = x - window.pageXOffset;
return x;
}
function slide(x) {
/*resize the image:*/
img.style.width = x + "px";
/*position the slider:*/
slider.style.left = img.offsetWidth - (slider.offsetWidth / 2) + "px";
}
}
}
initComparisons();* {box-sizing: border-box;}
.img-comp-container {
position: relative;
height: 200px; /*should be the same height as the images*/
}
.img-comp-img {
position: absolute;
width: auto;
height: auto;
overflow:hidden;
}
.img-comp-img img {
display:block;
vertical-align:middle;
}
.img-comp-slider {
position: absolute;
z-index:9;
cursor: ew-resize;
/*set the appearance of the slider:*/
width: 40px;
height: 40px;
background-color: #2196F3;
opacity: 0.7;
border-radius: 50%;
}<h1>Compare Two Images</h1>
<p>Click and slide the blue slider to compare two images:</p>
<div class="img-comp-container">
<div class="img-comp-img">
<img src="https://placeimg.com/640/480/animals" width="300" height="200">
</div>
<div class="img-comp-img img-comp-overlay">
<img src="https://placeimg.com/640/480/animals?t=1524676145713" width="300" height="200">
</div>
</div>
编辑：如果我只是添加另一个div将其全部包装并添加overflow：hidden，它实际上什么都不做。
答案 0 :(得分：1)
所以我有一个解决方案。非常简单。但是你必须知道.img-comp-container的宽度。当然还有overflow: hidden;
问题是，overflow: hidden;可以正常工作。但由于您的.img-comp-container是块样式元素，因此它跨越网页（或其父容器）的整个宽度。因此，为了不仅在垂直方向而且在水平方向上强制执行溢出，您必须将该div的宽度限制为“正确”隐藏它
function initComparisons() {
var x, i;
/*find all elements with an "overlay" class:*/
x = document.getElementsByClassName("img-comp-overlay");
for (i = 0; i < x.length; i++) {
/*once for each "overlay" element:
pass the "overlay" element as a parameter when executing the compareImages function:*/
compareImages(x[i]);
}
function compareImages(img) {
var slider, img, clicked = 0,
w, h;
/*get the width and height of the img element*/
w = img.offsetWidth;
h = img.offsetHeight;
/*set the width of the img element to 50%:*/
img.style.width = (w / 2) + "px";
/*create slider:*/
slider = document.createElement("DIV");
slider.setAttribute("class", "img-comp-slider");
/*insert slider*/
img.parentElement.insertBefore(slider, img);
/*position the slider in the middle:*/
slider.style.top = (h / 2) - (slider.offsetHeight / 2) + "px";
slider.style.left = (w / 2) - (slider.offsetWidth / 2) + "px";
/*execute a function when the mouse button is pressed:*/
slider.addEventListener("mousedown", slideReady);
/*and another function when the mouse button is released:*/
window.addEventListener("mouseup", slideFinish);
/*or touched (for touch screens:*/
slider.addEventListener("touchstart", slideReady);
/*and released (for touch screens:*/
window.addEventListener("touchstop", slideFinish);
function slideReady(e) {
/*prevent any other actions that may occur when moving over the image:*/
e.preventDefault();
/*the slider is now clicked and ready to move:*/
clicked = 1;
/*execute a function when the slider is moved:*/
window.addEventListener("mousemove", slideMove);
window.addEventListener("touchmove", slideMove);
}
function slideFinish() {
/*the slider is no longer clicked:*/
clicked = 0;
}
function slideMove(e) {
var pos;
/*if the slider is no longer clicked, exit this function:*/
if (clicked == 0) return false;
/*get the cursor's x position:*/
pos = getCursorPos(e)
/*prevent the slider from being positioned outside the image:*/
if (pos < 0) pos = 0;
if (pos > w) pos = w;
/*execute a function that will resize the overlay image according to the cursor:*/
slide(pos);
}
function getCursorPos(e) {
var a, x = 0;
e = e || window.event;
/*get the x positions of the image:*/
a = img.getBoundingClientRect();
/*calculate the cursor's x coordinate, relative to the image:*/
x = e.pageX - a.left;
/*consider any page scrolling:*/
x = x - window.pageXOffset;
return x;
}
function slide(x) {
/*resize the image:*/
img.style.width = x + "px";
/*position the slider:*/
slider.style.left = img.offsetWidth - (slider.offsetWidth / 2) + "px";
}
}
}
initComparisons();* {
box-sizing: border-box;
}
.img-comp-container {
position: relative;
height: 200px;
/*should be the same height as the images*/
/* Overflow must be here, and helping it up with width */
width: 300px;
overflow: hidden;
}
.img-comp-img {
position: absolute;
width: auto;
height: auto;
overflow: hidden;
}
.img-comp-img img {
display: block;
vertical-align: middle;
}
.img-comp-slider {
position: absolute;
z-index: 9;
cursor: ew-resize;
/*set the appearance of the slider:*/
width: 40px;
height: 40px;
background-color: #2196F3;
opacity: 0.7;
border-radius: 50%;
}<h1>Compare Two Images</h1>
<p>Click and slide the blue slider to compare two images:</p>
<div class="img-comp-container">
<div class="img-comp-img">
<img src="https://placeimg.com/640/480/animals" width="300" height="200">
</div>
<div class="img-comp-img img-comp-overlay">
<img src="https://placeimg.com/640/480/animals?t=1524676145713" width="300" height="200">
</div>
</div>