標籤:chrome 學習 span char code tom hello line image
While, generally speaking, HTML is for content and CSS is for presentation, JavaScript is for interactivity.
1、從HTML到JavaScript,像下面這樣:
<!DOCTYPE html><html> <head> <meta charset="UTF-8"> <title></title> </head> <body> <script> alert("Hello, world."); </script> </body></html>
alert的意思是警告,類似於message. 效果上就是彈出一個對話方塊。
2、引用外部的.js檔案
<!DOCTYPE html><html> <head> <meta charset="UTF-8"> <title></title> </head> <body> <script src="script.js"></script> </body></html>
script.js
alert("Hello, world.");
3、在瀏覽器Console中運行JavaScript代碼,Chrome進入Console的快速鍵是F12
4、在正式開始學習前,需要強調的是:
A browser then runs JavaScript line-by-line, starting at the top of the file or
script element and finishing at the bottom (unless you tell it to go elsewhere).
5、詢問使用者姓氏的小程式
<!DOCTYPE html><html> <head> <meta charset="UTF-8"> <title></title> </head> <body> <script type="text/javascript"> var surname = prompt(‘Greetings friend, may I enquire as to your surname?‘); </script> </body></html>
通過瀏覽器運行這段代碼,將跳出一個“小盒子”,詢問你的姓氏。
6、變數類似於一個“盒子”,我們利用它來儲存資料;它具有“名”和“值”。
聲明(Declaration)
var surname;var age;
初始化(Initialization)
var name = "Tom";
賦值(assignment)
name = "Andy";age = 43;
【JavaScript】筆記01——Making Stuff Happen???