鼠标拖动改变DIV等网页元素的大小的最佳实践
1.初次实现
1.1 html代码
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>div change width by drag</title> <script src="../jQuery/jquery-1.8.3.min.js" type="text/javascript"></script> </head> <body> <h1>div change width by drag</h1> <div id="pos" style="color:red"></div> <div id="myDiv" style="border:2px solid red;width:300px;height:50px;margin-left: 100px;margin-top: 20px"></div> </body> </html>
1.2 js代码
var eleLeft = $('#myDiv').offset().left; var isMouseDown = false; var borderLen = 4; //左右边框 $('#myDiv').bind({ mousedown:function(e){ var ele = $(this); var rightPos = eleLeft + ele.width() + borderLen; if(rightPos-5 <= e.pageX && e.pageX <= rightPos){ isMouseDown = true; } }, mousemove:function(e){ var ele = $(this); var rightPos = eleLeft + ele.width() + borderLen; $('#pos').text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos); if(rightPos-5 <= e.pageX && e.pageX <= rightPos){ ele.css('cursor','e-resize'); }else{ if(!isMouseDown){ ele.css('cursor','auto'); } } if(isMouseDown){ ele.width((e.pageX-eleLeft-borderLen)+'px'); //新鼠标位置-div距左-borderLen } }, mouseup:function(e){ isMouseDown = false; } });
1.3 结果
只能往左拖动使div宽度变小，往右拖动没有用！原因往右拖动鼠标mousemove事件无法被div捕获了。拖动时也很难停下来！所以得改进。
2.再次改进
$('#myDiv').bind({
mousedown:function(e){
var ele = $(this);
var rightPos = eleLeft + ele.width() + borderLen;
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
isMouseDown = true;
}
}
});
$('body').bind({
mousemove:function(e){
var ele = $('#myDiv');
var rightPos = eleLeft + ele.width() + borderLen;
$('#pos').text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos);
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
ele.css('cursor','e-resize');
}else{
if(!isMouseDown){
ele.css('cursor','auto');
}
}
if(isMouseDown){
ele.width((e.pageX-eleLeft-borderLen)+'px');
}
},
mouseup:function(e){
isMouseDown = false;
}
});
这次解决了上述问题，可以往右拖，并且随时可以停下来了。到这里就完成了吗？NO!
当我引入一个其他div，并且阻止mouseup事件冒泡情况怎么样呢？答案是，拖动到这个其它div上放开鼠标后无法停止下来！
<div id="otherDiv" style="border: 2px solid blue;width: 200px;height: 200px;margin-left: 400px"></div>
$('#otherDiv').mouseup(function(e){
//e.preventDefault(); //阻止默认行为
e.stopPropagation(); //阻止事件冒泡(导致body捕获不到mouseup事件)
});
3.完美解决
拖动停止可能受到其它元素的干扰，怎么解决？想到一些弹出层点击其它其它地方隐藏的功能，让我想到了，加一个遮罩层，让mouseup事件总是可以响应，不就搞定了嘛！
$('#myDiv').bind({
mousedown:function(e){
var ele = $(this);
var rightPos = eleLeft + ele.width() + borderLen;
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
isMouseDown = true;
//创建遮罩层，防止mouseup事件被其它元素阻止冒泡，导致mouseup事件无法被body捕获，导致拖动不能停止
var bodyWidth = $('body').width();
var bodyHeight = $('body').height();
$('body').append('<div id="mask" style="opacity:0.2;top:0px;left:0px;background-color:green;position:absolute;z-index:9999;width:'+bodyWidth+'px;height:'+bodyHeight+'px;"></div>');
}
}
});
$('body').bind({
mousemove:function(e){
var ele = $('#myDiv');
var rightPos = eleLeft + ele.width() + borderLen;
$('#pos').text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos);
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
ele.css('cursor','e-resize');
}else{
if(!isMouseDown){
ele.css('cursor','auto');
}
}
if(isMouseDown){
ele.width((e.pageX-eleLeft-borderLen)+'px');
}
},
mouseup:function(e){
isMouseDown = false;
$('#mask').remove();
}
});
$('#otherDiv').mouseup(function(e){
//e.preventDefault(); //阻止默认行为
e.stopPropagation(); //阻止事件冒泡(导致body捕获不到mouseup事件)
});
4.完整代码和最终效果
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>div change width by drag</title> <script src="../jQuery/jquery-1.8.3.min.js" type="text/javascript"></script> </head> <body> <h1>div change width by drag</h1> <div id="pos" style="color:red"></div> <div id="myDiv" style="border:2px solid red;width:300px;height:50px;margin-left: 100px;margin-top: 20px"></div> <div id="otherDiv" style="border: 2px solid blue;width: 200px;height: 200px;margin-left: 400px"></div> </body> <script type="text/javascript"> $(document).ready(function(){ var eleLeft = $('#myDiv').offset().left; var isMouseDown = false; var borderLen = 4; //左右边框 $('#myDiv').bind({ mousedown:function(e){ var ele = $(this); var rightPos = eleLeft + ele.width() + borderLen; if(rightPos-5 <= e.pageX && e.pageX <= rightPos){ isMouseDown = true; //创建遮罩层，防止mouseup事件被其它元素阻止冒泡，导致mouseup事件无法被body捕获，导致拖动不能停止 var bodyWidth = $('body').width(); var bodyHeight = $('body').height(); $('body').append('<div id="mask" style="opacity:0.2;top:0px;left:0px;background-color:green;position:absolute;z-index:9999;width:'+bodyWidth+'px;height:'+bodyHeight+'px;"></div>'); } } }); $('body').bind({ mousemove:function(e){ var ele = $('#myDiv'); var rightPos = eleLeft + ele.width() + borderLen; $('#pos').text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos); if(rightPos-5 <= e.pageX && e.pageX <= rightPos){ ele.css('cursor','e-resize'); }else{ if(!isMouseDown){ ele.css('cursor','auto'); } } if(isMouseDown){ ele.width((e.pageX-eleLeft-borderLen)+'px'); } }, mouseup:function(e){ isMouseDown = false; $('#mask').remove(); } }); $('#otherDiv').mouseup(function(e){ //e.preventDefault(); //阻止默认行为 e.stopPropagation(); //阻止事件冒泡(导致body捕获不到mouseup事件) }); }); </script> </html>
