面向Java程序员的JavaScript教程

1. Java & Script

2. JavaScript Java

5. ,
Java JavaScript
,
Java JavaScript

6. Java + Script
=
Groovy || JRuby || Scala

7. Java + Script
|!=|
JavaScript

8. JavaScript is

9. JavaScript is
JavaScript

12. +

13. Code:
new Boolean(true) == true
new Boolean(true) === false

14. Code:
var a = “”;
if (a) {
alert(a);
}

15. • new Boolean(true) true
• == ===
• if (a) a

16. •
•
•

17. •5
null undefined

18. • 20
• true
• ”hello, world!”
• [12, 30, true, “hello”]
• {name: “qingyu”, id: 17300}

20. • == ===
• === ==
• ECMA

21. Tips
•
• ===
==

22. Code:
var price = 100;
function doSomething() {
var doublePrice = price * 2;
var price = 200;
var halfPrice = price / 2;
alert(doublePrice);
alert(halfPrice);
}
doSomething();
alert(price);

23. Code:
var color = “red”;
if (true) {
var color = “blue”;
alert(color);
}
alert(color);

24. • var doublePrice = price * 2 var halfPrice
= price / 2 price
• color

25. •
•

26. • var var
•

27. •

28. Tips
•

29. Code:
var a = 0 && true;
var b = true && 2;
var c = 0 || 3;
var cfg = {maxHeight: 200};
var d = cfg.height || cfg.maxHeight;

30. Code:
// 0
var check = function(obj) {
return !!(obj || obj === 0);
};

31. • && ||
• && ||
• !!a a

32. Tips
• ||
• !!

33. Code:
(function() {
//code here
})();

35. var fn = function() {
//code here
};
fn();

36. var fn = function() {
//code here
};
fn();

37. var fn = function() {
//code here
};
fn();

38. (function() {
//code here
}) ();

39. Code:
var createComparisonFunction = function(propertyName) {
return function(object1, object2) {
var value1 = object1[propertyName], value2 = object2[propertyName];
if (value1 < value2) { return -1; }
else if (value1 > value2) { return 1; }
else { return 0; }
};
}
var fn = createComparisonFunction(‘id’);

40. •
•
•

41. •

43. Tips
•

44. Code:
var sum = function() {
var result = 0;
for(var i = 0, len = arguments.length; i < len; I++) {
result += arguments[i];
}
return result;
};
var total = sum(10, 20, 30);

45. Code:
function factorial(num) {
if (num <= 1) {
return 1;
} else {
return num * arguments.callee(num - 1);
}
}

46. Code:
function sum(num1, num2) {
return num1 + num2;
}
function callSum1(num1, num2) {
return sum.apply(this, [num1, num2]);
}
function callSum2(num1, num2) {
return sum.call(this, num1, num2);
}

47. • Function
•
• arguments
• apply call

48. Code:
window.color = “red”;
var obj = {color: “blue”};
function sayColor() {
alert(this.color);
}
sayColor();
obj.sayColor = sayColor;
obj.sayColor();

49. Code:
var Dog = function(msg) {
this.msg = msg;
this.shout = function() { alert(this.msg); };
this.waitAndShout = function() {
setTimeout(function() { alert(this.msg) }, 5000);
};
};

50. this
• Java
• this
• this window
this

51. Code:
var Person = function(name) {
this.name = name;
this.sayName = function() {
alert(this.name);
};
};
var person1 = new Person(“Jack”);
person1.sayName();

52. Code:
var Person = function() {};
Person.prototype.name = “Jack”;
Person. prototype.sayName = function() {
alert(this.name);
};
var person1 = new Person();
person1.sayName();

53. •
•

55. Tips
• Peron
Person.prototype

56. Code:
function SuperType() { this.property = true; }
SuperType.prototype.getSuperValue = function() {
return this.property;
};
function SubType() { this.subProperty = false; }
SubType.prototype = new SuperType();
SubType.prototype.getSubValue = function() {
return this. subProperty;
};

57. Code:
var instance = new SubType();
alert(instance.getSuperValue());
alert(instance.getSubValue());
alert(instance instanceof Object);
alert(instance instanceof SuperType);
alert(instance instanceof SubType);

58. • 1. ; 2. SubType.prototype; 3.
SuperType.prototype;

60. •
•
•
•

61. YUI

63. Thanks