Javascript防止父div之外的可拖动div [英] Javascript Prevent Draggable div outside parent div
本文介绍了Javascript防止父div之外的可拖动div的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有可拖动的div。我希望使用JavaScript在父级内限制此可拖动div。我知道如何使用jQuery UI可拖动插件来防止可拖动div。但是我不确定如何使用本机JavaScript来限制可拖动对象。请在我的代码下面找到：
I have draggable div. I want this draggable div to be restricted within parent using javascript. I know how to prevent draggable div using jquery UI draggable plugin. But I am not sure how to restrict draggable using native javascript. Please find below my code:
<!DOCTYPE HTML>
<html>
<head>
<style>
.draggabletarget {
float: left;
width: 100px;
height: 35px;
margin: 15px;
padding: 10px;
border: 1px solid #aaaaaa;
}
</style>
</head>
<body>
<div class="parent" style="border:1px solid red;height:600px;width:600px;">
<div class="draggabletarget" ondragstart="dragStart(event)" ondrag="dragging(event)" draggable="true" id="dragtarget">
<p >Drag me!</p>
</div>
</div>
<script>
function dragStart(event) {
event.dataTransfer.setData("Text", event.target.id);
}
function dragging(event) {
document.getElementById("demo").innerHTML = "The p element is being dragged";
}
function allowDrop(event) {
event.preventDefault();
}
</script>
</body>
</html>
在此代码中，我有一个class父类的div。我希望班级为draggabletarget的可拖动div不应拖到父div之外。我如何在本机javascript中做到这一点。请提出建议
In this code i have a div with class parent. I want my draggable div whose class is draggabletarget shouldn't drag outside the parent div. How can i do this in native javascript. Please suggest
推荐答案
function $(el){
return document.getElementById(el);
}
var isDragging = false;
var tzdragg = function(){
return {
move : function(divid,xpos,ypos){
var a = $(divid);
$(divid).style.left = xpos + 'px';
$(divid).style.top = ypos + 'px';
},
setDragging : function() {
isDragging = true;
},
resetDragging : function() {
isDragging = false;
},
startMoving : function(evt){
evt = evt || window.event;
var posX = evt.clientX,
posY = evt.clientY,
a = $('elem'),
divTop = a.style.top,
divLeft = a.style.left;
divTop = divTop.replace('px','');
divLeft = divLeft.replace('px','');
var diffX = posX - divLeft,
diffY = posY - divTop;
document.onmousemove = function(evt){
evt = evt || window.event;
var posX = evt.clientX,
posY = evt.clientY,
aX = posX - diffX,
aY = posY - diffY;
var boun=document.getElementById("parent").offsetWidth-document.getElementById("elem").offsetWidth;
if((aX>0)&&(aX<boun)&&(aY>0)&&(aY<boun))
tzdragg.move('elem',aX,aY);
}
},
stopMoving : function(){
var a = document.createElement('script');
document.onmousemove = function(){}
if(!isDragging) {
console.log('clicked');
}
},
}
}();
#elem
{
position: absolute;
width: 100px;
height: 100px;
background-color: black;
-webkit-user-select: none;
-moz-user-select: none;
-o-user-select: none;
-ms-user-select: none;
-khtml-user-select: none;
user-select: none;
cursor: default;
}
<div style="height:400px; width:400px; border:solid 1px black;position: absolute;top: 0;
left: 0;" id='parent'>
<div id='elem' onmousedown='tzdragg.resetDragging();tzdragg.startMoving(event);' onmouseup='tzdragg.stopMoving();' onmousemove='tzdragg.setDragging();'
>
</div>
</div>
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