JavaScript基础入门：常用方法与技巧详解

JavaScript基础入门：常用方法与技巧详解

本文档适用于对JavaScript完全陌生，但希望掌握其核心用法、迈向熟练应用的开发者。

预备知识：HTML

JavaScript基础知识：脚本嵌入与处理

JavaScript基础教程第一部分：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>

此方法可确保在不支持JavaScript的浏览器中，相关代码不会被执行，避免显示原始代码。

3. 浏览器不支持时的替代显示

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浏览器输出：DOM操作与时间处理

JavaScript基础教程第二部分：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>