JavaScript就这么回事 (JS基础知识整理)

来源：互联网发布：论文数据分析方法编辑：程序博客网时间：2024/05/30 04:52

1 创建脚本块

引用内容程序代码
<script language=”JavaScript”>
JavaScript 代码写在这里面
</script>

2 隐藏脚本代码
引用内容程序代码
<script language=”JavaScript”>
<!–
document.write(“Hello”);
// –>
</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
引用内容程序代码
<noscript>
Hello to the non-JavaScript browser.
</noscript>

4 链接外部脚本文件
引用内容程序代码
<script language=”JavaScript” src=”/”filename.js””></script>

5 注释脚本
引用内容程序代码
// This is a comment
document.write(“Hello”); // This is a comment
/*
All of this
is a comment
*/

6 输出到浏览器
引用内容程序代码
document.write(“<strong>Hello</strong>”);

7 定义变量
引用内容程序代码
var myVariable = “some value”;

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

9 字符串搜索
引用内容程序代码
<script language=”JavaScript”>
<!–
var myVariable = “Hello there”;
var therePlace = myVariable.search(“there”);
document.write(therePlace);
// –>
</script>

10 字符串替换
引用内容程序代码
thisVar.replace(“Monday”,”Friday”);

11 格式化字串
引用内容程序代码
<script language=”JavaScript”>
<!–
var myVariable = “Hello there”;
document.write(myVariable.big() + “<br>”);
document.write(myVariable.blink() + “<br>”);
document.write(myVariable.bold() + “<br>”);
document.write(myVariable.fixed() + “<br>”);
document.write(myVariable.fontcolor(“red”) + “<br>”);
document.write(myVariable.fontsize(“18pt”) + “<br>”);
document.write(myVariable.italics() + “<br>”);
document.write(myVariable.small() + “<br>”);
document.write(myVariable.strike() + “<br>”);
document.write(myVariable.sub() + “<br>”);
document.write(myVariable.sup() + “<br>”);
document.write(myVariable.toLowerCase() + “<br>”);
document.write(myVariable.toUpperCase() + “<br>”);
var firstString = “My String”;
var finalString = firstString.bold().toLowerCase().fontcolor(“red”);
// –>
</script>

12 创建数组
引用内容程序代码
<script language=”JavaScript”>
<!–
var myArray = new Array(5);
myArray[0] = “First Entry”;
myArray[1] = “Second Entry”;
myArray[2] = “Third Entry”;
myArray[3] = “Fourth Entry”;
myArray[4] = “Fifth Entry”;
var anotherArray = new Array(“First Entry”,”Second Entry”,”Third Entry”,”Fourth Entry”,”Fifth Entry”);
// –>
</script>

13 数组排序
引用内容程序代码
<script language=”JavaScript”>
<!–
var myArray = new Array(5);
myArray[0] = “z”;
myArray[1] = “c”;
myArray[2] = “d”;
myArray[3] = “a”;
myArray[4] = “q”;
document.write(myArray.sort());
// –>
</script>

14 分割字符串
引用内容程序代码
<script language=”JavaScript”>
<!–
var myVariable = “a,b,c,d”;
var stringArray = myVariable.split(“,”);
document.write(stringArray[0]);
document.write(stringArray[1]);
document.write(stringArray[2]);
document.write(stringArray[3]);
// –>
</script>

15 弹出警告信息
引用内容程序代码
<script language=”JavaScript”>
<!–
window.alert(“Hello”);
// –>
</script>

16 弹出确认框
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<script language=”JavaScript”>
<!–
var result = window.confirm(“Click OK to continue”);
// –>
</script>

17 自定义函数
引用内容程序代码
<script language=”JavaScript”>
<!–
function multiple(number1,number2) {
var result = number1 * number2;
return result;
}
// –>
</script>

18 调用JS函数
引用内容程序代码
<a href=”#” onClick=”functionName()”>Link text</a>
<a href=”/”javascript:functionName”()”>Link text</a>

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

20 条件判断
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<script>
<!–
var userChoice = window.confirm(“Choose OK or Cancel”);
var result = (userChoice == true) ? “OK” : “Cancel”;
document.write(result);
// –>
</script>

21 指定次数循环
引用内容程序代码
<script>
<!–
var myArray = new Array(3);
myArray[0] = “Item 0”;
myArray[1] = “Item 1”;
myArray[2] = “Item 2”;
for (i = 0; i < myArray.length; i++) {
document.write(myArray[i] + “<br>”);
}
// –>
</script>

22 设定将来执行
引用内容程序代码
<script>
<!–
function hello() {
window.alert(“Hello”);
}
window.setTimeout(“hello()”,5000);
// –>
</script>

23 定时执行函数
引用内容程序代码
<script>
<!–
function hello() {
window.alert(“Hello”);
window.setTimeout(“hello()”,5000);
}