本文详细介绍JavaScript的基础知识及实用技巧，包括脚本创建、数组操作、日期处理等，旨在帮助读者掌握核心概念并提升开发效率。
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
<script language=”JavaScript”> JavaScript code goes here</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 comment2: document.write(“Hello”); // This is a comment
3: /*
4: All of this5: 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 page3: </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 page3: </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 = “http://www.liu21st.com/”;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>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='#' 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: }
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