DOM-BOM-EVENT（5）
5.宽、高、位置相关
5.1.clientX/clientY
clientX和clientY表示鼠标在浏览器可视区的坐标位置
<script>
document.onclick = function(ev){
var ev = ev || event
alert("clientX:"+ev.clientX+", clientY:"+ev.clientY)
}
</script>
5.2.pageX/pageY
pageX和pageY表示鼠标在网页文档中的坐标位置，这里需要注意：网页的宽高是可以大于浏览器可视区的
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#box{
width: 300px;
height: 2000px;
background-color: #009f95;
}
</style>
</head>
<body>
<div id="box"></div>
<script>
document.onclick = function(ev){
var ev = ev || event
alert("clientX:"+ev.pageX+", clientY:"+ev.pageY)
}
</script>
</body>
</html>
5.3.offsetLeft/offsetTop/offsetWidth/offsetHeight/offsetParent
offsetLeft和offsetTop是相对于定位父级的坐标位置
offsetWidth和offsetHeight是元素实体所占的总宽高，例如：总宽度 = 内容 + padding + border
offsetParent表示定位父级
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#box{
width: 400px;
height: 400px;
background-color: #009f95;
position: absolute;
left: 200px;
top:100px;
}
#box-inner{
width: 100px;
height: 100px;
background-color: orangered;
position: absolute;
left: 50px;
top: 50px;
padding: 50px;
}
</style>
</head>
<body style="position:relative">
<div id="box">
<div id="box-inner"></div>
</div>
<script>
var oBoxIner = document.getElementById("box-inner")
var oBox = document.getElementById("box")
document.onclick = function(ev){
var ev = ev || event
// 获取left 和 top偏移量
alert("offsetLeft:"+oBoxIner.offsetLeft+", offsetTop:"+oBoxIner.offsetTop)
// 获取当前元素的宽高, width = 内容宽高+padding+border
alert("offsetWidth:"+oBoxIner.offsetWidth+", offsetHeight:"+oBoxIner.offsetHeight)
// 获取元素的最近的定位父级
console.log("offsetParent:"+oBoxIner.offsetParent)
}
</script>
</body>
</html>
5.4.scrollLeft/scrollTop／scrollWidth/scrollHeight
scrollLeft 和 scrollTop 表示元素滚出去的距离
scrollWidth和scrollHeight 对象的实际内容的宽高，会随对象中内容超过可视区后而变大
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#box{
width: 300px;
height: 200px;
border: 5px solid black;
margin: 100px auto;
overflow: auto;
/* box-sizing: border-box; */
}
#box-inner{
width: 450px;
margin: 100px auto;
height: 300px;
border: 1px solid red;
background-color: #009f95
}
</style>
</head>
<body>
<div id="box">
<div id="box-inner"></div>
</div>
<script>
var oBox = document.getElementById("box")
var oBoxInner = document.getElementById("box-inner")
oBox.onclick = function(){
// 顶部滚动距离
alert("scrollTop:"+this.scrollTop+"scrollLeft:"+this.scrollLeft)
alert("scrollWidth:"+this.scrollWidth+",scrollHeight:"+this.scrollHeight)
}
</script>
</body>
</html>
5.5.clientWidth/clientHeight
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#box{
width: 400px;
height: 400px;
background-color: #009f95;
position: absolute;
left: 200px;
top:100px;
}
#box-inner{
width: 100px;
height: 100px;
background-color: orangered;
position: absolute;
left: 50px;
top: 50px;
padding: 50px;
border: 20px solid black;
}
</style>
</head>
<body style="position:relative">
<div id="box">
<div id="box-inner"></div>
</div>
<script>
var oBoxIner = document.getElementById("box-inner")
var oBox = document.getElementById("box")
document.onclick = function(ev){
var ev = ev || event
//元素可视区宽高， 内容+padding 不包括边框
alert("clientWidth:"+oBoxIner.clientWidth+", clientHeight:"+oBoxIner.clientHeight)
}
</script>
</body>
</html>
5.6.总结
offsetWidth／offsetHeight clientWidth/clientHeight scrollWidth/scrollHeight
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#box{
width: 300px;
height: 200px;
border: 5px solid black;
margin: 100px auto;
overflow: auto;
padding: 20px;
}
#box-inner{
width: 450px;
margin: 100px 300px;
height: 300px;
border: 1px solid red;
background-color: #009f95
}
</style>
</head>
<body>
<div id="box">
<div id="box-inner"></div>
</div>
<script>
var oBox = document.getElementById("box")
var oBoxInner = document.getElementById("box-inner")
oBox.onclick = function(){
// 顶部滚动距离
console.log("有滚动条的时候-----》")
console.log("scrollWidth:"+this.scrollWidth)
//offsetWidth
console.log("offsetWidth-----》")
console.log("offsetWith:"+this.offsetWidth)
// clientWidth
console.log("clientWidth-----》")
console.log("clientWidth:"+this.clientWidth)
}
</script>
</body>
</html>
总结： 1. clientWidth和offsetWidth返回的值和内部元素无关，它们两个的区别是，前者返回的值是：width+padding ，后者返回的值是：width+padding+border 2. scrollWidth返回的值和内部的元素有关，它返回的是内部元素实际的宽带，包括margin、padding、border等 等，会随着内部元素所占宽度的增加而增加
5.7.如何获取文档的宽／高？
document.documentElement.scrollWidth/scrollHeight
5.8.如何获取可视区宽／高？
docuement.documentElement.clientWidth document.documentElement.clientHeight
5.9.如何获取页面的滚动距离？
document.documentElement.scrollTop/scrollLeft
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