我正在尝试制作一个带有两个框的网络应用程序,其中一个框位于另一个框内。用户应该能够点击并移动内部框,但是,用户不应该能够将此框移动到外部框的范围之外。用户可以通过将内部框拖动到外部框的边缘之一来移动外部框。我知道如何移动内部框,但问题是如何在此限制下移动其他框。有人能帮帮我吗?以下是我所做的:
<!doctype html>
<head>
<title>JavaScript Game</title>
<style>
#container {
height:400px;
width:600px;
outline: 1px solid black;
position:absolute;
left:50px;
top: 0px;
background-color:green;
}
#guy {
position:absolute;
height:50px;
width:50px;
outline: 1px solid black;
background-color:red;
left: 200px;
top: 200px;
}
</style>
</head>
<body>
<div id="container"></div>
<div id="guy"></div>
<script>
var guy=document.getElementById("guy");
var cont=document.getElementById("container");
var lastX,lastY; // Tracks the last observed mouse X and Y position
guy.addEventListener("mousedown", function(event) {
if (event.which == 1) {
lastX = event.pageX;
lastY = event.pageY;
addEventListener("mousemove", moved);
event.preventDefault(); // Prevent selection
}
});
function buttonPressed(event) {
if (event.buttons == null)
return event.which != 0;
else
return event.buttons != 0;
}
function moved(event) {
if (!buttonPressed(event)) {
removeEventListener("mousemove", moved);
} else {
var distX = event.pageX - lastX;
var distY = event.pageY - lastY;
guy.style.left =guy.offsetLeft + distX + "px";
guy.style.top = guy.offsetTop + distY + "px";
lastX = event.pageX;
lastY = event.pageY;
}
}
</script>
</body>