Javascript – 第2页

2月 16, 2023

js数组赋值、遍历需要注意的问题

作者 5xue 在 Javascript

js数组赋值时不要跳跃式赋值，以免出现异常。如下面例子：

var arr=[];
arr["0"]="全部";
arr["1"]="Flash";
arr["2"]="Html";
arr["3"]="Css";
arr["4"]="JavaScript";
arr["5"]="Php";
arr["6"]="数据库";
arr["7"]="服务器";
arr["99"]="其它";

//遍历数组
//方法1：
for (let item of arr) {
	//循环100次
	console.log("方法1：" + item);
}

//方法2：
arr.forEach((item,index)=>{
	//循环10次
	console.log("方法2：" + item);
})

//方法3：
for (let i in arr) {
	//循环10次
	console.log("方法3：" + arr[i]);
}

//方法4：
for (let i = 0; i < arr.length; i ++) {
	//循环100次
	console.log("方法4：" + arr[i]);
}

var arr=[];

arr["0"]="全部";

arr["1"]="Flash";

arr["2"]="Html";

arr["3"]="Css";

arr["4"]="JavaScript";

arr["5"]="Php";

arr["6"]="数据库";

arr["7"]="服务器";

arr["99"]="其它";

//遍历数组

//方法1：

for (let item of arr) {

//循环100次

console.log("方法1：" + item);

}

//方法2：

arr.forEach((item,index)=>{

//循环10次

console.log("方法2：" + item);

})

//方法3：

for (let i in arr) {

//循环10次

console.log("方法3：" + arr[i]);

}

//方法4：

for (let i = 0; i < arr.length; i ++) {

//循环100次

console.log("方法4：" + arr[i]);

}

浏览样例：http://5xue.cc/wp-content/uploads/samples/20230216

2月 11, 2023

js实现圆形进度条

作者 5xue 在 Javascript

js实现圆形进度条，源代码：

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>js实现圆形进度条</title>
<style>
.container {
	width: 300px;
	height: 300px;
	margin: 100px auto;
	/* border: 1px solid #000; */
}
.circle-progressbar {
	position: relative;
	width: 100%;
	height: 100%;
}
.circle-progressbar .title {
	margin: 0;
	text-align: center;
	line-height: 300px;
}
.circle-progressbar div {
	box-sizing: border-box;
}
.circle-progressbar .wrapper {
	position: absolute;
	top: 0;
	width: 150px;
	height: 300px;
	/* border: 1px solid red; */
	overflow: hidden;
}
.circle-progressbar .wrapper.left-wrapper {
	left: 0;
}
.circle-progressbar .wrapper.right-wrapper {
	right: 0;
}
.circle-progressbar .wrapper .circle-bar {
	position: absolute;
	width: 300px;
	height: 300px;
	border: 30px solid transparent;
	border-radius: 50%;
	transform: rotate(-135deg);
	transition: transform .3s;
}
.circle-progressbar .left-wrapper .circle-bar {
	left: 0;
	border-left-color: turquoise;
	border-bottom-color: turquoise;
}
.circle-progressbar .right-wrapper .circle-bar {
	right: 0;
	border-right-color: turquoise;
	border-top-color: turquoise;
}
</style>
</head>
<body>
<div class="container">
	<div class="circle-progressbar">
		<h1 class="title">0%</h1>
		<div class="wrapper left-wrapper">
			<div class="circle-bar"></div>
		</div>
		<div class="wrapper right-wrapper">
			<div class="circle-bar"></div>
		</div>
	</div>
</div>
<script>
const circleProgressBar = CircleProgressBar();
let p = 0;
let t = setInterval(() => {circleProgressBar( ++ p)}, 200);

function CircleProgressBar() {
	const oLeftCircleBar = getCircleBar('left'),
		oRightCircleBar = getCircleBar('right'),
		oTitle = document.querySelector('.circle-progressbar .title');

	return function(percent) {
		if(percent >= 0 && percent <= 50) {
			setRotate(oRightCircleBar, percent)
		}else if(percent >= 50 && percent <= 100) {
			setRotate(oLeftCircleBar, percent - 50)
		}
		if(percent >= 0 && percent <= 100) {
			oTitle.innerText = percent + '%';
		}
		if(percent == 100) {
			t=window.clearInterval(t);
		}
	}

	function formatDegree(percent) {
		return `rotate(${ -135 + (360 / 100 * percent) }deg)`
	}

	function setRotate(node, percent) {
		node.style.transform = formatDegree(percent)
	}

	function getCircleBar(dir) {
		return document.querySelector(`.circle-progressbar .${ dir }-wrapper .circle-bar`);
	}
}
</script>
</body>
</html>

100

101

102

103

104

105

106

107

108

109

110

111

112

113

<!DOCTYPE html>

<html>

<head>

<title>js实现圆形进度条</title>

<style>

.container {

width: 300px;

height: 300px;

margin: 100px auto;

/* border: 1px solid #000; */

}

.circle-progressbar {

position: relative;

width: 100%;

height: 100%;

}

.circle-progressbar .title {

margin: 0;

text-align: center;

line-height: 300px;

}

.circle-progressbar div {

box-sizing: border-box;

}

.circle-progressbar .wrapper {

position: absolute;

top: 0;

width: 150px;

height: 300px;

/* border: 1px solid red; */

overflow: hidden;

}

.circle-progressbar .wrapper.left-wrapper {

left: 0;

}

.circle-progressbar .wrapper.right-wrapper {

right: 0;

}

.circle-progressbar .wrapper .circle-bar {

position: absolute;

width: 300px;

height: 300px;

border: 30px solid transparent;

border-radius: 50%;

transform: rotate(-135deg);

transition: transform .3s;

}

.circle-progressbar .left-wrapper .circle-bar {

left: 0;

border-left-color: turquoise;

border-bottom-color: turquoise;

}

.circle-progressbar .right-wrapper .circle-bar {

right: 0;

border-right-color: turquoise;

border-top-color: turquoise;

}

</style>

</head>

<body>

</div>

</div>

const circleProgressBar = CircleProgressBar();

let p = 0;

let t = setInterval(() => {circleProgressBar( ++ p)}, 200);

function CircleProgressBar() {

const oLeftCircleBar = getCircleBar('left'),

oRightCircleBar = getCircleBar('right'),

oTitle = document.querySelector('.circle-progressbar .title');

return function(percent) {

if(percent >= 0 && percent <= 50) {

setRotate(oRightCircleBar, percent)

}else if(percent >= 50 && percent <= 100) {

setRotate(oLeftCircleBar, percent - 50)

}

if(percent >= 0 && percent <= 100) {

oTitle.innerText = percent + '%';

}

if(percent == 100) {

t=window.clearInterval(t);

}

function formatDegree(percent) {

return `rotate(${ -135 + (360 / 100 * percent) }deg)`

}

function setRotate(node, percent) {

node.style.transform = formatDegree(percent)

}

function getCircleBar(dir) {

return document.querySelector(`.circle-progressbar .${ dir }-wrapper .circle-bar`);

}

</script>

</body>

</html>

浏览样例

1月 20, 2021

JS实现页面部分内容打印

作者 5xue 在 Html与Css, Javascript

原理：在页面内嵌入一个隐藏的iframe，把要打印的内容赋值给iframe，再利用iframe的print()方法，实现打印。

主页面代码

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JS实现页面部分内容打印</title>
<style>
button {
	display: block;
	padding: 2px 20px 4px 20px;
}
.ifr1 {
	width:530px;
	height:120px;
	display:none;
}
.div1, .div2 {
	width:300px;
	line-height:100px;
	border:1px solid #000;
	margin-bottom:20px;
	text-align:center;
}
</style>
<script type="text/javascript">
function myPrint() {
	var iwindow = window.frames['ifr1'];
	var idoc = iwindow.document;
	idoc.getElementById("myDiv").innerHTML = document.getElementById("div2").innerHTML;
	iwindow.print();
}
</script>
</head>
<body>
	<div id="div1"><div class="div1">This is div1</div></div>
	<div id="div2"><div class="div2">This is div2</div></div>
	<button onclick="myPrint()">打印Div2</button>
	<iframe name="ifr1" src="iframe.html" class="ifr1"></iframe>
</body>
</html>

<!DOCTYPE html>

<html>

<head>

<title>JS实现页面部分内容打印</title>

<style>

button {

display: block;

padding: 2px 20px 4px 20px;

}

.ifr1 {

width:530px;

height:120px;

display:none;

}

.div1, .div2 {

width:300px;

line-height:100px;

border:1px solid #000;

margin-bottom:20px;

text-align:center;

}

</style>

function myPrint() {

var iwindow = window.frames['ifr1'];

var idoc = iwindow.document;

idoc.getElementById("myDiv").innerHTML = document.getElementById("div2").innerHTML;

iwindow.print();

}

</script>

</head>

<body>

<button onclick="myPrint()">打印Div2</button>

</body>

</html>

iframe.html页面代码

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>iframe页面</title>
<style>
body {
	padding:0;
	margin:0 auto;
}
#myDiv {
	text-align:center;
}
.div2 {
	margin: 0 auto;
	width:500px;
	line-height:50px;
	font-size:24px;
	font-weight:bold;
	text-align:center;
	margin-top:10px;
	border:1px solid #ff0000;
}
</style>
</head>
<body>
	<div id="myDiv">This is iframe</div>
</body>
</html>

<!DOCTYPE html>

<html>

<head>

<title>iframe页面</title>

<style>

body {

padding:0;

margin:0 auto;

}

#myDiv {

text-align:center;

}

.div2 {

margin: 0 auto;

width:500px;

line-height:50px;

font-size:24px;

font-weight:bold;

text-align:center;

margin-top:10px;

border:1px solid #ff0000;

}

</style>

</head>

<body>

<div id="myDiv">This is iframe</div>

</body>

</html>

说明：在iframe.html页面，对样式div2重新进行了设定。

1月 19, 2021

在父页面内设置iframe页面内容

作者 5xue 在 Javascript

一、父页面代码
1. jquery

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>在父页面内设置iframe元素内容</title>
<script type="text/javascript" src="js/jquery.min.js"></script>
<script type="text/javascript">
function setIframe() {
	$("#iframe").contents().find("#div1").html($("#div1").html());
}
</script>
</head>
<body>
	<div id="div1">This is a test</div>
	<iframe id="iframe" src="iframe.html"></iframe>
	<div><button onclick="setIframe()">设置</button></div>
</body>
</html>

<!DOCTYPE html>

<html>

<head>

<title>在父页面内设置iframe元素内容</title>

function setIframe() {

$("#iframe").contents().find("#div1").html($("#div1").html());

}

</script>

</head>

<body>

</body>

</html>

2. 原生

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>在父页面内设置iframe元素内容</title>
<script type="text/javascript">
function setIframe() {
	var iframe = document.getElementById("ifr1");
	var iwindow = iframe.contentWindow;
	var idoc = iwindow.document;
	idoc.getElementById("div1").innerHTML = document.getElementById("div1").innerHTML;
}
</script>
</head>
<body>
	<div id="div1">This is a test</div>
	<iframe id="ifr1" src="iframe.html"></iframe>
	<div><button onclick="setIframe()">设置</button></div>
</body>
</html>

<!DOCTYPE html>

<html>

<head>

<title>在父页面内设置iframe元素内容</title>

function setIframe() {

var iframe = document.getElementById("ifr1");

var iwindow = iframe.contentWindow;

var idoc = iwindow.document;

idoc.getElementById("div1").innerHTML = document.getElementById("div1").innerHTML;

}

</script>

</head>

<body>

</body>

</html>

或者

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>在父页面内设置iframe元素内容</title>
<script type="text/javascript">
function setIframe() {
	var iwindow = window.frames['ifr1'];
	var idoc = iwindow.document;
	idoc.getElementById("div1").innerHTML = document.getElementById("div1").innerHTML;
}
</script>
</head>
<body>
	<div id="div1">This is a test</div>
	<iframe id="ifr1" name="ifr1" src="iframe.html"></iframe>
	<div><button onclick="setIframe()">设置</button></div>
</body>
</html>

<!DOCTYPE html>

<html>

<head>

<title>在父页面内设置iframe元素内容</title>

function setIframe() {

var iwindow = window.frames['ifr1'];

var idoc = iwindow.document;

idoc.getElementById("div1").innerHTML = document.getElementById("div1").innerHTML;

}

</script>

</head>

<body>

</body>

</html>

二、iframe页面代码

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>iframe页面</title>
</head>
<body>
	<div id="div1">This is iframe</div>
</body>
</html>

<!DOCTYPE html>

<html>

<head>

<title>iframe页面</title>

</head>

<body>

<div id="div1">This is iframe</div>

</body>

</html>

分类目录Javascript