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JavaScript的方法和技巧


 这篇介绍javascript方面的日志,我在是Clang上看到的。作者介绍挺全面的,所以转载过来让感兴趣的朋友看一下。呵呵~~~ 

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, 
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 
JavaScript就这么回事1:基础知识 

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: <!--

3: document.write(“Hello”);

4: // -- >

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: <!--

3: var myVariable = “Hello there”;

4: var therePlace = myVariable.search(“there”);

5: document.write(therePlace);

6: // -- >

7: </script >


10 字符串替换

1: thisVar.replace(“Monday”,”Friday”);


11 格式化字串

1: <script language=”JavaScript” >

2: <!--

3: var myVariable = “Hello there”;

4: document.write(myVariable.big() + “ <br >”);

5: document.write(myVariable.blink() + “ <br >”);

6: document.write(myVariable.bold() + “ <br >”);

7: document.write(myVariable.fixed() + “ <br >”);

8: document.write(myVariable.fontcolor(“red”) + “ <br >”);

9: document.write(myVariable.fontsize(“18pt”) + “ <br >”);

10: document.write(myVariable.italics() + “ <br >”);

11: document.write(myVariable.small() + “ <br >”);

12: document.write(myVariable.strike() + “ <br >”);

13: document.write(myVariable.sub() + “ <br >”);

14: document.write(myVariable.sup() + “ <br >”);

15: document.write(myVariable.toLowerCase() + “ <br >”);

16: document.write(myVariable.toUpperCase() + “ <br >”);

17:

18: var firstString = “My String”;

19: var finalString = firstString.bold().toLowerCase().fontcolor(“red”);

20: // -- >

21: </script >


12 创建数组

1: <script language=”JavaScript” >

2: <!--

3: var myArray = new Array(5);

4: myArray[0] = “First Entry”;

5: myArray[1] = “Second Entry”;

6: myArray[2] = “Third Entry”;

7: myArray[3] = “Fourth Entry”;

8: myArray[4] = “Fifth Entry”;

9: var anotherArray = new Array(“First Entry”,”Second Entry”,”Third Entry”,”Fourth Entry”,”Fifth Entry”);

10: // -- >

11: </script >


13 数组排序

1: <script language=”JavaScript” >

2: <!--

3: var myArray = new Array(5);

4: myArray[0] = “z”;

5: myArray[1] = “c”;

6: myArray[2] = “d”;

7: myArray[3] = “a”;

8: myArray[4] = “q”;

9: document.write(myArray.sort());

10: // -- >

11: </script >


14 分割字符串

1: <script language=”JavaScript” >

2: <!--

3: var myVariable = “a,b,c,d”;

4: var stringArray = myVariable.split(“,”);

5: document.write(stringArray[0]);

6: document.write(stringArray[1]);

7: document.write(stringArray[2]);

8: document.write(stringArray[3]);

9: // -- >

10: </script >


15 弹出警告信息

1: <script language=”JavaScript” >

2: <!--

3: window.alert(“Hello”);

4: // -- >

5: </script >


16 弹出确认框

1: <script language=”JavaScript” >

2: <!--

3: var result = window.confirm(“Click OK to continue”);

4: // -- >

5: </script >


17 定义函数

1: <script language=”JavaScript” >

2: <!--

3: function multiple(number1,number2) {

4: var result = number1 * number2;

5: return result;

6: }

7: // -- >

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: <!--

3: var userChoice = window.confirm(“Choose OK or Cancel”);

4: var result = (userChoice == true) ? “OK” : “Cancel”;

5: document.write(result);

6: // -- >

7: </script >


21 指定次数循环

1: <script >

2: <!--

3: var myArray = new Array(3);

4: myArray[0] = “Item 0”;

5: myArray[1] = “Item 1”;

6: myArray[2] = “Item 2”;

7: for (i = 0; i < myArray.length; i++) {

8: document.write(myArray[i] + “ <br >”);

9: }

10: // -- >

11: </script >


22 设定将来执行

1: <script >

2: <!--

3: function hello() {

4: window.alert(“Hello”);

5: }

6: window.setTimeout(“hello()”,5000);

7: // -- >

8: </script >


23 定时执行函数

1: <script >

2: <!--

3: function hello() {

4: window.alert(“Hello”);

5: window.setTimeout(“hello()”,5000);

6: }

7: window.setTimeout(“hello()”,5000);

8: // -- >

9: </script >


24 取消定时执行

1: <script >

2: <!--

3: function hello() {

4: window.alert(“Hello”);

5: }

6: var myTimeout = window.setTimeout(“hello()”,5000);

7: window.clearTimeout(myTimeout);

8: // -- >

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(“&amp;”);

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 = “http://www.liu21st.com/”;

3: </script >


35 添加网页加载进度窗口

1: <html >

2: <head >

3: <script language= &amp;apos;javaScript &amp;apos; >

4: var placeHolder = window.open( &amp;apos;holder.html &amp;apos;, &amp;apos;placeholder &amp;apos;, &amp;apos;width=200,height=200 &amp;apos;);

5: </script >

6: <title >The Main Page </title >

7: </head >

8: <body onLoad= &amp;apos;placeHolder.close() &amp;apos; >

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



还是先继续写完JS就这么回事系列吧~


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= &amp;apos;# &amp;apos; onClick= &amp;apos;window.alert(document.myForm.myText.value); &amp;apos; >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= &apos;# &apos; onClick= &apos;alert(document.myForm.mySelect.value); &apos; >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: }

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