Helllo, fellow StackOverflow community! For the past few weeks, I have been working on a drag-and-drop for HTML/JavaScript. Basically, I have a circle and two boxes. The circle can be dragged to anywhere on the screen. However, I need it so the circle can only be dropped within one of the two boxes. Despite several days of research, I could not figure out how to do this. Thank you in advance!
<!DOCTYPE html>
<html>
<head>
<meta name="viewport"
content="width=device-width,
initial-scale=1.0,
user-scalable=no" />
<title>Drag/Drop/Bounce</title>
<style>
#item {
width: 100px;
height: 100px;
background-color: rgb(245, 230, 99);
border: 10px solid rgba(136, 136, 136, .5);
border-radius: 50%;
touch-action: none;
user-select: none;
}
#box1 {
width: 200px;
height: 200px;
background-color: red;
}
#box2 {
width: 200px;
height: 200px;
background-color: lightblue;
}
</style>
</head>
<body>
<h1>Drag and Drop</h1>
<div id="box1">
<div id="item"></div>
</div>
<br>
<div id="box2"></div>
<script>
var dragItem = document.querySelector("#item");
var container = dragItem;
//Declare Variables
var active = false;
var currentX;
var currentY;
var initialX;
var initialY;
var xOffset = 0;
var yOffset = 0;
//Add Event Listeners for Touchscreens
container.addEventListener("touchstart", dragStart, false);
container.addEventListener("touchend", dragEnd, false);
container.addEventListener("touchmove", drag, false);
//Add Event Listeners for Mice
container.addEventListener("mousedown", dragStart, false);
container.addEventListener("mouseup", dragEnd, false);
container.addEventListener("mousemove", drag, false);
function dragStart(e) { //when the drag starts
if (e.type === "touchstart") { //if its a touchscreen
initialX = e.touches[0].clientX - xOffset; //set initial x-cordinate to where it was before drag started
initialY = e.touches[0].clientY - yOffset; //set initial y-cordinate to where it was before drag started
} else { //if its not a touchscreen (mouse)
initialX = e.clientX - xOffset; //set initial x-cordinate to where it was before drag started
initialY = e.clientY - yOffset; //set initial y-cordinate to where it was before drag started
}
if (e.target === dragItem) { //if user is dragging circle
active = true; //the drag is active
}
}
function dragEnd(e) { //when the drag ends
initialX = currentX; //set the initial x-cordinate to where it is now
initialY = currentY; //set the initial y-cordinate to where it is now
active = false; //the drag is no longer active
}
function drag(e) { //when the circle is being dragged
if (active) { //if the drag is active
e.preventDefault(); //the user cant do anything else but drag
if (e.type === "touchmove") { //if its a touchscreen
currentX = e.touches[0].clientX - initialX; //set current x-cordinate to where it is now
currentY = e.touches[0].clientY - initialY; //set current y-cordinate to where it is now
} else { //if its not a touchscreen (mouse)
currentX = e.clientX - initialX; //set current x-cordinate to where it is now
currentY = e.clientY - initialY; //set current y-cordinate to where it is now
}
//Im not sure what this does but it dosnt work without it
xOffset = currentX;
yOffset = currentY;
setTranslate(currentX, currentY, dragItem);
}
}
function setTranslate(xPos, yPos, el) { //Im not sure what this does but it dosnt work without it
el.style.transform = "translate3d(" + xPos + "px, " + yPos + "px, 0)";
}
</script>
</body>
</html>
I've also uploaded the code to TryIt for those who prefer: https://www.w3schools.com/code/tryit.asp?filename=GCF4V2RIT7T4
In this version you can move the circle only inside the red box. I think you can take that and easily implement the other box.
<!DOCTYPE html> <html> <head> <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no" /> <title>Drag/Drop/Bounce</title> <style> #item { width: 100px; height: 100px; background-color: rgb(245, 230, 99); border: 10px solid rgba(136, 136, 136, .5); border-radius: 50%; touch-action: none; user-select: none; position: absolute; } #box1 { width: 200px; height: 200px; background-color: red; } #box2 { width: 200px; height: 200px; background-color: lightblue; } </style> </head> <body> <h1>Drag and Drop</h1> <div id="item"></div> <div id="box1"> </div> <br> <div id="box2"></div> <script> var dragItem = document.querySelector("#item"); var box1 = document.querySelector("#box1"); var box2 = document.querySelector("#box2"); var container = dragItem; //Declare Variables var active = false; var currentX; var currentY; var initialX; var initialY; var xOffset = 0; var yOffset = 0; //Add Event Listeners for Touchscreens container.addEventListener("touchstart", dragStart, false); container.addEventListener("touchend", dragEnd, false); container.addEventListener("touchmove", drag, false); //Add Event Listeners for Mice container.addEventListener("mousedown", dragStart, false); container.addEventListener("mouseup", dragEnd, false); container.addEventListener("mousemove", drag, false); function dragStart(e) { //when the drag starts if (e.type === "touchstart") { //if its a touchscreen initialX = e.touches[0].clientX - xOffset; //set initial x-cordinate to where it was before drag started initialY = e.touches[0].clientY - yOffset; //set initial y-cordinate to where it was before drag started } else { //if its not a touchscreen (mouse) initialX = e.clientX - xOffset; //set initial x-cordinate to where it was before drag started initialY = e.clientY - yOffset; //set initial y-cordinate to where it was before drag started } if (e.target === dragItem) { //if user is dragging circle active = true; //the drag is active } } function dragEnd(e) { //when the drag ends const box1Size = box1.getBoundingClientRect() const elementSize = dragItem.getBoundingClientRect() if (elementSize.left >= box1Size.left && elementSize.right <= box1Size.right && elementSize.top >= box1Size.top && elementSize.bottom <= box1Size.bottom) { initialX = currentX; //set the initial x-cordinate to where it is now initialY = currentY; //set the initial y-cordinate to where it is now } else { currentX = 0 currentY = 0 initialX = 0 initialY = 0 xOffset = 0; yOffset = 0; setTranslate(0, 0, dragItem); } active = false; //the drag is no longer active } function drag(e) { //when the circle is being dragged if (active) { //if the drag is active e.preventDefault(); //the user cant do anything else but drag if (e.type === "touchmove") { //if its a touchscreen currentX = e.touches[0].clientX - initialX; //set current x-cordinate to where it is now currentY = e.touches[0].clientY - initialY; //set current y-cordinate to where it is now } else { //if its not a touchscreen (mouse) currentX = e.clientX - initialX; //set current x-cordinate to where it is now currentY = e.clientY - initialY; //set current y-cordinate to where it is now } //Im not sure what this does but it dosnt work without it xOffset = currentX; yOffset = currentY; setTranslate(currentX, currentY, dragItem); } } function setTranslate(xPos, yPos, el) { //Im not sure what this does but it dosnt work without it el.style.transform = "translate3d(" + xPos + "px, " + yPos + "px, 0)"; } </script> </body> </html>
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