JavaScript就这么回事

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JavaScript就这么回事1：基础知识
有些时候你精通一门语言，但是会发现你其实整天在和其它语言打交道，也许你以为这些微不足道，不至于影响你的开发进度，但恰恰是这些你不重视的东西会浪费你很多时间，我一直以为我早在几年前就已经精通JavaScript了，直到目前，我才越来越觉得JavaScript 远比我想象的复杂和强大，我开始崇拜它，就像崇拜所有OOP语言一样～
趁着节日的空隙，把有关JavaScript的方法和技巧整理下，让每个在为JavaScript而烦恼的人明白，JavaScript就这么回事！并希望JavaScript还可以成为你的朋友，让你豁然开朗，在项目中更好的应用～
适合阅读范围：对JavaScript一无所知～离精通只差一步之遥的人
基础知识：HTML

1 创建脚本块
1: <script language=”JavaScript”>
2: JavaScript code goes here
3: </script>

2 隐藏脚本代码
1: <script language=”JavaScript”>
2: 
5: </script>

在不支持JavaScript的浏览器中将不执行相关代码

3 浏览器不支持的时候显示
1: <noscript>
2: Hello to the non-JavaScript browser.
3: </noscript>

4 链接外部脚本文件
1: <script language=”JavaScript” src=”filename.js”></script>

5 注释脚本
1: // This is a comment
2: document.write(“Hello”); // This is a comment
3: /*
4: All of this
5: is a comment
6: */

6 输出到浏览器
1: document.write(“<strong>Hello</strong>”);

7 定义变量
1: var myVariable = “some value”;

8 字符串相加
1: var myString = “String1” + “String2”;

9 字符串搜索
1: <script language=”JavaScript”>
2: 
7: </script>

10 字符串替换
1: thisVar.replace(“Monday”,”Friday”);

11 格式化字串
1: <script language=”JavaScript”>
2: 
21: </script>

12 创建数组
1: <script language=”JavaScript”>
2: 
11: </script>

13 数组排序
1: <script language=”JavaScript”>
2: 
11: </script>

14 分割字符串
1: <script language=”JavaScript”>
2: 
10: </script>

15 弹出警告信息
1: <script language=”JavaScript”>
2: 
5: </script>

16 弹出确认框
1: <script language=”JavaScript”>
2: 
5: </script>

17 定义函数
1: <script language=”JavaScript”>
2: 
8: </script>

18 调用JS函数
1: <a href=”#” onClick=”functionName()”>Link text</a>
2: <a href=”javascript:functionName()”>Link text</a>

19 在页面加载完成后执行函数
1: <body onLoad=”functionName();”>
2: Body of the page
3: </body>

20 条件判断
1: <script>
2: 
7: </script>

21 指定次数循环
1: <script>
2: 
11: </script>

22 设定将来执行
1: <script>
2: 
8: </script>

23 定时执行函数
1: <script>
2: 
9: </script>

24 取消定时执行
1: <script>
2: 
9: </script>

25 在页面卸载时候执行函数
1: <body onUnload=”functionName();”>
2: Body of the page
3: </body>

JavaScript就这么回事2：浏览器输出
26 访问document对象
1: <script language=”JavaScript”>
2: var myURL = document.URL;
3: window.alert(myURL);
4: </script>

27 动态输出HTML
1: <script language=”JavaScript”>
2: document.write(“<p>Here’s some information about this document:</p>”);
3: document.write(“<ul>”);
4: document.write(“<li>Referring Document: “ + document.referrer + “</li>”);
5: document.write(“<li>Domain: “ + document.domain + “</li>”);
6: document.write(“<li>URL: “ + document.URL + “</li>”);
7: document.write(“</ul>”);
8: </script>

28 输出换行
1: document.writeln(“<strong>a</strong>”);
2: document.writeln(“b”);

29 输出日期
1: <script language=”JavaScript”>
2: var thisDate = new Date();
3: document.write(thisDate.toString());
4: </script>

30 指定日期的时区
1: <script language=”JavaScript”>
2: var myOffset = -2;
3: var currentDate = new Date();
4: var userOffset = currentDate.getTimezoneOffset()/60;
5: var timeZoneDifference = userOffset - myOffset;
6: currentDate.setHours(currentDate.getHours() + timeZoneDifference);
7: document.write(“The time and date in Central Europe is: “ + currentDate.toLocaleString());
8: </script>

31 设置日期输出格式
1: <script language=”JavaScript”>
2: var thisDate = new Date();
3: var thisTimeString = thisDate.getHours() + “:” + thisDate.getMinutes();
4: var thisDateString = thisDate.getFullYear() + “/” + thisDate.getMonth() + “/” + thisDate.getDate();
5: document.write(thisTimeString + “ on “ + thisDateString);
6: </script>

32 读取URL参数
1: <script language=”JavaScript”>
2: var urlParts = document.URL.split(“?”);
3: var parameterParts = urlParts[1].split(“&”);
4: for (i = 0; i < parameterParts.length; i++) {
5: var pairParts = parameterParts[i].split(“=”);
6: var pairName = pairParts[0];
7: var pairValue = pairParts[1];
8: document.write(pairName + “ ：“ +pairValue );
9: }
10: </script>
你还以为HTML是无状态的么？

33 打开一个新的document对象
1: <script language=”JavaScript”>
2: function newDocument() {
3: document.open();
4: document.write(“<p>This is a New Document.</p>”);
5: document.close();
6: }
7: </script>

34 页面跳转
1: <script language=”JavaScript”>
2: window.location = “[url]http://www.liu21st.com/[/url]”;
3: </script>

35 添加网页加载进度窗口
1: <html>
2: <head>
3: <script language='javaScript'>
4: var placeHolder = window.open('holder.html','placeholder','width=200,height=200');
5: </script>
6: <title>The Main Page</title>
7: </head>
8: <body onLoad='placeHolder.close()'>
9: <p>This is the main page</p>
10: </body>
11: </html>

JavaScript就这么回事3：图像
36 读取图像属性
1: <img src=”image1.jpg” name=”myImage”>
2: <a href=”# ” onClick=”window.alert(document.myImage.width)”>Width</a>
3:

37 动态加载图像
1: <script language=”JavaScript”>
2: myImage = new Image;
3: myImage.src = “Tellers1.jpg”;
4: </script>

38 简单的图像替换
1: <script language=”JavaScript”>
2: rollImage = new Image;
3: rollImage.src = “rollImage1.jpg”;
4: defaultImage = new Image;
5: defaultImage.src = “image1.jpg”;
6: </script>
7: <a href=”myUrl” onMouseOver=”document.myImage.src = rollImage.src;”
8: onMouseOut=”document.myImage.src = defaultImage.src;”>
9: <img src=”image1.jpg” name=”myImage” width=100 height=100 border=0>

39 随机显示图像
1: <script language=”JavaScript”>
2: var imageList = new Array;
3: imageList[0] = “image1.jpg”;
4: imageList[1] = “image2.jpg”;
5: imageList[2] = “image3.jpg”;
6: imageList[3] = “image4.jpg”;
7: var imageChoice = Math.floor(Math.random() * imageList.length);
8: document.write(‘<img src=”’ + imageList[imageChoice] + ‘“>’);
9: </script>

40 函数实现的图像替换
1: <script language=”JavaScript”>
2: var source = 0;
3: var replacement = 1;
4: function createRollOver(originalImage,replacementImage) {
5: var imageArray = new Array;
6: imageArray[source] = new Image;
7: imageArray[source].src = originalImage;
8: imageArray[replacement] = new Image;
9: imageArray[replacement].src = replacementImage;
10: return imageArray;
11: }
12: var rollImage1 = createRollOver(“image1.jpg”,”rollImage1.jpg”);
13: </script>
14: <a href=”#” onMouseOver=”document.myImage1.src = rollImage1[replacement].src;”
15: onMouseOut=”document.myImage1.src = rollImage1[source].src;”>
16: <img src=”image1.jpg” width=100 name=”myImage1” border=0>
17: </a>

41 创建幻灯片
1: <script language=”JavaScript”>
2: var imageList = new Array;
3: imageList[0] = new Image;
4: imageList[0].src = “image1.jpg”;
5: imageList[1] = new Image;
6: imageList[1].src = “image2.jpg”;
7: imageList[2] = new Image;
8: imageList[2].src = “image3.jpg”;
9: imageList[3] = new Image;
10: imageList[3].src = “image4.jpg”;
11: function slideShow(imageNumber) {
12: document.slideShow.src = imageList[imageNumber].src;
13: imageNumber += 1;
14: if (imageNumber < imageList.length) {
15: window.setTimeout(“slideShow(“ + imageNumber + “)”,3000);
16: }
17: }
18: </script>
19: </head>
20: <body onLoad=”slideShow(0)”>
21: <img src=”image1.jpg” width=100 name=”slideShow”>

42 随机广告图片
1: <script language=”JavaScript”>
2: var imageList = new Array;
3: imageList[0] = “image1.jpg”;
4: imageList[1] = “image2.jpg”;
5: imageList[2] = “image3.jpg”;
6: imageList[3] = “image4.jpg”;
7: var urlList = new Array;
8: urlList[0] = “http://some.host/”;
9: urlList[1] = “http://another.host/”;
10: urlList[2] = “http://somewhere.else/”;
11: urlList[3] = “http://right.here/”;
12: var imageChoice = Math.floor(Math.random() * imageList.length);
13: document.write(‘<a href=”’ + urlList[imageChoice] + ‘“><img src=”’ + imageList[imageChoice] + ‘“></a>’);
14: </script>

JavaScript就这么回事4：表单
43 表单构成
1: <form method=”post” action=”target.html” name=”thisForm”>
2: <input type=”text” name=”myText”>
3: <select name=”mySelect”>
4: <option value=”1”>First Choice</option>
5: <option value=”2”>Second Choice</option>
6: </select>
7: <br>
8: <input type=”submit” value=”Submit Me”>
9: </form>

44 访问表单中的文本框内容
1: <form name=”myForm”>
2: <input type=”text” name=”myText”>
3: </form>
4: <a href='#' onClick='window.alert(document.myForm.myText.value);'>Check Text Field</a>

45 动态复制文本框内容
1: <form name=”myForm”>
2: Enter some Text: <input type=”text” name=”myText”><br>
3: Copy Text: <input type=”text” name=”copyText”>
4: </form>
5: <a href=”#” onClick=”document.myForm.copyText.value =
6: document.myForm.myText.value;”>Copy Text Field</a>

46 侦测文本框的变化
1: <form name=”myForm”>
2: Enter some Text: <input type=”text” name=”myText” onChange=”alert(this.value);”>
3: </form>

47 访问选中的Select
1: <form name=”myForm”>
2: <select name=”mySelect”>
3: <option value=”First Choice”>1</option>
4: <option value=”Second Choice”>2</option>
5: <option value=”Third Choice”>3</option>
6: </select>
7: </form>
8: <a href='#' onClick='alert(document.myForm.mySelect.value);'>Check Selection List</a>

48 动态增加Select项
1: <form name=”myForm”>
2: <select name=”mySelect”>
3: <option value=”First Choice”>1</option>
4: <option value=”Second Choice”>2</option>
5: </select>
6: </form>
7: <script language=”JavaScript”>
8: document.myForm.mySelect.length++;
9: document.myForm.mySelect.options[document.myForm.mySelect.length - 1].text = “3”;
10: document.myForm.mySelect.options[document.myForm.mySelect.length - 1].value = “Third Choice”;
11: </script>

49 验证表单字段
1: <script language=”JavaScript”>
2: function checkField(field) {
3: if (field.value == “”) {
4: window.alert(“You must enter a value in the field”);
5: field.focus();
6: }
7: }
8: </script>
9: <form name=”myForm” action=”target.html”>
10: Text Field: <input type=”text” name=”myField”onBlur=”checkField(this)”>
11: <br><input type=”submit”>
12: </form>

50 验证Select项
1: function checkList(selection) {
2: if (selection.length == 0) {
3: window.alert(“You must make a selection from the list.”);
4: return false;
5: }
6: return true;
7: }

51 动态改变表单的action
1: <form name=”myForm” action=”login.html”>
2: Username: <input type=”text” name=”username”><br>
3: Password: <input type=”password” name=”password”><br>
4: <input type=”button” value=”Login” onClick=”this.form.submit();”>
5: <input type=”button” value=”Register” onClick=”this.form.action = ‘register.html’; this.form.submit();”>
6: <input type=”button” value=”Retrieve Password” onClick=”this.form.action = ‘password.html’; this.form.submit();”>
7: </form>

52 使用图像按钮
1: <form name=”myForm” action=”login.html”>
2: Username: <input type=”text” name=”username”><br>
3: Password: <input type=”password”name=”password”><br>
4: <input type=”image” src=”login.gif” value=”Login”>
5: </form>
6:

53 表单数据的加密
1: <SCRIPT LANGUAGE='JavaScript'>
2: 
17: </SCRIPT>
18: <form name='myForm' onSubmit='encryptForm(this); window.alert(this.myField.value);'>
19: Enter Some Text: <input type=text name=myField><input type=submit>
20: </form>

上面的encryptForm方法把表单中的数据转换为编码，在提交表单之前完成了简单的表单数据加密～