5xue – 第41页 – 吾学网

1月 20, 2021

JS实现页面部分内容打印

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>

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<!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>

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<!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>

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<!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>

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<!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>

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<!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>

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<!DOCTYPE html>

<html>

<head>

<title>iframe页面</title>

</head>

<body>

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

</body>

</html>

1月 10, 2021

明油做法

作者 5xue 在饮食

2021-01-10
原料：葱段、姜片、洋葱丝、八角、花椒、香叶、花生油

做法：烧油5成热加洋葱丝翻炒2分钟，加葱段、姜片继续翻炒3分钟，加八角、花椒、香叶翻炒3分钟，然后捞出所有食材即可。

总结：油可以加更多一点。

1月 9, 2021

可预防数据库攻击的mysql_real_escape_string函数

作者 5xue 在 php开发, 数据库

下例代码没使用mysql_real_escape_string()函数：

<?php
$con = mysql_connect("localhost", "hello", "321");
if (!$con) {
	die('Could not connect: ' . mysql_error());
}
$sql = "SELECT * FROM users WHERE user='{$_POST['user']}' AND password='{$_POST['pwd']}'";
mysql_query($sql);

...

mysql_close($con);
?>

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<?php

$con = mysql_connect("localhost", "hello", "321");

if (!$con) {

die('Could not connect: ' . mysql_error());

}

$sql = "SELECT * FROM users WHERE user='{$_POST['user']}' AND password='{$_POST['pwd']}'";

mysql_query($sql);

...

mysql_close($con);

?>

如果用户输入信息如下：
$_POST[‘user’] = “john”;
$_POST[‘pwd’] = “‘ OR ‘‘=‘”;

则SQL查询会成为这样：
SELECT * FROM users WHERE user=’john’ AND password=” OR ”=”

这意味着用户不用输入正确信息也可以通过sql的查询语句，获得相应权限。

上述代码存在着很大的安全隐患，如果改成这样，则会好很多：

<?php
$con = mysql_connect("localhost", "hello", "321");
if (!$con) {
	die('Could not connect: ' . mysql_error());
}
$uname = mysql_real_escape_string($_POST['user']);
$upwd = mysql_real_escape_string($_POST['pwd']);
$sql = "SELECT * FROM users WHERE user='{$uname}' AND password='{$upwd}'";
mysql_query($sql);

...

mysql_close($con);
?>

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<?php

$con = mysql_connect("localhost", "hello", "321");

if (!$con) {

die('Could not connect: ' . mysql_error());

}

$uname = mysql_real_escape_string($_POST['user']);

$upwd = mysql_real_escape_string($_POST['pwd']);

$sql = "SELECT * FROM users WHERE user='{$uname}' AND password='{$upwd}'";

mysql_query($sql);

...

mysql_close($con);

?>

mysql_real_escape_string()函数对下列字符产生影响：
● \x00
● \n
● \r
● \
● ‘
● ”
● \x1a

参考资料：http://www.w3school.com.cn/php/func_mysql_real_escape_string.asp

此例已验证。

作者：5xue