JavaScript基础知识
1 创建脚本块
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<script language=”JavaScript”>
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JavaScript code goes here
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</script>
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2 隐藏脚本代码
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<script language=”JavaScript”>
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<!--
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document.write(“Hello”);
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// -->
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</script>
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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
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<noscript>
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Hello to the non-JavaScript browser.
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</noscript>
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4 链接外部脚本文件
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<script language=”JavaScript” src="/”filename.js"”></script> ![](https://www.cnblogs.com/Images/OutliningIndicators/None.gif)
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5 注释脚本
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// This is a comment
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document.write(“Hello”); // This is a comment
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/*
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All of this is a comment
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*/
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6 输出到浏览器
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document.write(“<strong>Hello</strong>”);
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7 定义变量
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var myVariable = “some value”;
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8 字符串相加
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var myString = “String1” + “String2”; ![](https://www.cnblogs.com/Images/OutliningIndicators/None.gif)
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9 字符串搜索
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<script language=”JavaScript”>
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<!--
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var myVariable = “Hello there”;
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var therePlace = myVariable.search(“there”);
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document.write(therePlace);
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// -->
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</script> ![](https://www.cnblogs.com/Images/OutliningIndicators/None.gif)
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10 字符串替换
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11 格式化字串
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<script language=”JavaScript”>
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<!--
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var myVariable = “Hello there”;
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document.write(myVariable.big() + “<br>”);
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document.write(myVariable.blink() + “<br>”);
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document.write(myVariable.bold() + “<br>”);
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document.write(myVariable.fixed() + “<br>”);
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document.write(myVariable.fontcolor(“red”) + “<br>”);
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document.write(myVariable.fontsize(“18pt”) + “<br>”);
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document.write(myVariable.italics() + “<br>”);
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document.write(myVariable.small() + “<br>”);
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document.write(myVariable.strike() + “<br>”);
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document.write(myVariable.sub() + “<br>”);
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document.write(myVariable.sup() + “<br>”);
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document.write(myVariable.toLowerCase() + “<br>”);
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document.write(myVariable.toUpperCase() + “<br>”);
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var firstString = “My String”;
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var finalString = firstString.bold().toLowerCase().fontcolor(“red”);
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// -->
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</script>
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12 创建数组
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<script language=”JavaScript”>
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<!--
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var myArray = new Array(5);
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myArray[0] = “First Entry”;
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myArray[1] = “Second Entry”;
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myArray[2] = “Third Entry”;
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myArray[3] = “Fourth Entry”;
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myArray[4] = “Fifth Entry”;
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var anotherArray = new Array(“First Entry”,”Second Entry”,”Third Entry”,”Fourth Entry”,”Fifth Entry”);
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// -->
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</script>
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13 数组排序
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<script language=”JavaScript”>
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<!--
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var myArray = new Array(5);
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myArray[0] = “z”;
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myArray[1] = “c”;
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myArray[2] = “d”;
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myArray[3] = “a”;
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myArray[4] = “q”;
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document.write(myArray.sort());
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// -->
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</script>
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14 分割字符串
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<script language=”JavaScript”>
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<!--
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var myVariable = “a,b,c,d”;
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var stringArray = myVariable.split(“,”);
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document.write(stringArray[0]);
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document.write(stringArray[1]);
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document.write(stringArray[2]);
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document.write(stringArray[3]);
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// -->
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</script>
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15 弹出警告信息
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<script language=”JavaScript”>
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<!--
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window.alert(“Hello”);
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// -->
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</script>
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16 弹出确认框
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<script language=”JavaScript”>
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<!--
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var result = window.confirm(“Click OK to continue”);
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// -->
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</script>
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17 定义函数
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<script language=”JavaScript”>
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<!--
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function multiple(number1,number2) {
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var result = number1 * number2;
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return result;
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}
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// -->
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</script>
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18 调用JS函数
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<a href=”#” onClick=”functionName()”>Link text</a>
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<a href="/”javascript:functionName"()”>Link text</a>
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19 在页面加载完成后执行函数
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<body onLoad=”functionName();”>
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Body of the page
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</body>
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20 条件判断
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<script>
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<!--
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var userChoice = window.confirm(“Choose OK or Cancel”);
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var result = (userChoice == true) ? “OK” : “Cancel”;
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document.write(result);
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// -->
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</script>
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21 指定次数循环
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<script>
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var myArray = new Array(3);
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myArray[0] = “Item 0”;
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myArray[1] = “Item 1”;
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myArray[2] = “Item 2”;
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for (i = 0; i < myArray.length; i++) {
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document.write(myArray[i] + “<br>”);
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}
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// -->
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</script>
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22 设定将来执行
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<script>
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function hello() {
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window.alert(“Hello”);
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}
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window.setTimeout(“hello()”,5000);
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// -->
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</script>
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23 定时执行函数
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<script>
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<!--
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function hello() {
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window.alert(“Hello”);
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window.setTimeout(“hello()”,5000);
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}
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window.setTimeout(“hello()”,5000);
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// -->
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</script>
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24 取消定时执行
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<script>
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function hello() {
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window.alert(“Hello”);
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}
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var myTimeout = window.setTimeout(“hello()”,5000);
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window.clearTimeout(myTimeout);
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// -->
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</script>
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25 在页面卸载时候执行函数
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<body onUnload=”functionName();”>
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Body of the page
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</body>
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