JavaScript basic introductory syntax collection_basic knowledge

For novices, if you master the following methods, you can basically make some js yourself, which is a must for getting started

Create script block

Hide script code



Browse



Link to external script file



Comment script

// This is a comment
document .write(“Hello”); // This is a comment
/*
All of this
is a comment
*/

Output to browser

document.write(“Output content”);

Define variables

var myVariable = “some value”;

characters String addition

var myString = “String1” “String2”;

String search



String replacement

thisVar.replace(“Monday”,”Friday”);

Format string

< ;script language="JavaScript">



Create array



Array sorting



Split string



Pop up warning message



Pop-up confirmation box



Call JS function

< ;a href="#" onClick="functionName()">Link text
Link text

Execute the function after the page is loaded


Body of the page


Conditional judgment

<script> <br><!-- <br/>var userChoice = window.confirm(“Choose OK or Cancel”); <br/>var result = (userChoice == true) ? “OK” : “Cancel”; <br/>document.write(result); <br/>// --> <br></script>

指定次数循环

<script> <br><!-- <br>var myArray = new Array(3); <br>myArray[0] = “Item 0”; <br>myArray[1] = “Item 1”; <br>myArray[2] = “Item 2”; <br>for (i = 0; i < myArray.length; i ) { <br>document.write(myArray “<br>”); <br>} <br>// --> <br></script>

设定将来执行

<script> <br><!-- <br/>function hello() { <br/>window.alert(“Hello”); <br/>} <br/>window.setTimeout(“hello()”,5000); <br/>// --> <br></script>

定时执行函数

<script> <br><!-- <br/>function hello() { <br/>window.alert(“Hello”); <br/>window.setTimeout(“hello()”,5000); <br/>} <br/>window.setTimeout(“hello()”,5000); <br/>// --> <br></script>

取消定时执行

<script> <br><!-- <br/>function hello() { <br/>window.alert(“Hello”); <br/>} <br/>var myTimeout = window.setTimeout(“hello()”,5000); <br/>window.clearTimeout(myTimeout); <br/>// --> <br></script>

在页面卸载时候执行函数

Body of the page