javascript 之基本知识
压缩器
1.JSMin
2.Dojo ShrinkSafe
3.YUI Compressor
单元测试
1.JsUnit
2.YUI Test
3.DOH
4.qUnit
文档生成器
1.JsDoc Toolkit
2.YUI Doc
3.AjaxDoc
获取元素
getElementByTagName
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>Shopping list</title>
<style type="text/css">
p {
color: yellow;
font-family: "arial", sans-serif;
font-size: 1.2em;
}
body {
color: white;
background-color: black;
}
#purchases {
border: 1px solid white;
background-color: #333;
color: #ccc;
padding: 1em;
}
#purchases li {
font-weight: bold;
}
</style>
</head>
<body>
<h1>What to buy</h1>
<p title="a gentle reminder">Don't forget to buy this stuff.</p>
<p>This is just a test</p>
<ul id="purchases">
<li>A tin of beans</li>
<li>Cheese</li>
<li>Milk</li>
</ul>
<script type="text/JavaScript">
var paras = document.getElementsByTagName("p");
for (var i=0; i< paras.length; i++) {
var title_text = paras[i].getAttribute("title");
if (title_text != null) {
alert(title_text);
}
}
</script>
</body>
</html>
数值转换
1.Number() 2.parseInt(); 3.parseFloat();
var num1 = Number("Hello world!"); //NaN
var num2 = Number(""); //0
var num3 = Number("000011"); //11
var num4 = Number(true); //1
var num1 = parseInt("1234blue"); //1234
var num2 = parseInt(""); //NaN
var num3 = parseInt("0xA"); //10 - hexadecimal
var num4 = parseInt(22.5); //22
var num5 = parseInt("70"); //70 - decimal
var num6 = parseInt("0xf"); //15 ?hexadecimal
var num1 = parseInt("AF", 16); //175
var num2 = parseInt("AF"); //NaN
var num1 = parseInt("10", 2); //2 ?parsed as binary
var num2 = parseInt("10", 8); //8 ?parsed as octal
var num3 = parseInt("10", 10); //10 ?parsed as decimal
var num4 = parseInt("10", 16); //16 ?parsed as
var num1 = parseFloat("1234blue"); //1234 - integer
var num2 = parseFloat("0xA"); //0
var num3 = parseFloat("22.5"); //22.5
var num4 = parseFloat("22.34.5"); //22.34
var num5 = parseFloat("0908.5"); //908.5
var num6 = parseFloat("3.125e7"); //31250000
String 操作
var age = 11; var ageAsString = age.toString(); //the string "11" var found = true; var foundAsString = found.toString(); //the string "true" alert(ageAsString); alert(typeof ageAsString); alert(foundAsString); alert(typeof foundAsString); var num = 10; alert(num.toString()); //"10" alert(num.toString(2)); //"1010" alert(num.toString(8)); //"12" alert(num.toString(10)); //"10" alert(num.toString(16)); //"a" var value1 = 10; var value2 = true; var value3 = null; var value4; alert(String(value1)); //"10" alert(String(value2)); //"true" alert(String(value3)); //"null" alert(String(value4)); //"undefined"
Object 类型
var person = new Object();
person.name = "Nicholas";
person.age = 29;
var person = {
name : "Nicholas",
age : 29
};
Array类型
var colors = new Array(3); //create an array with three items
var names = new Array("Greg"); //create an array with one item, the string "Greg"
alert(colors.length);
alert(names.length);
var colors = ["red", "blue", "green"]; //creates an array with three strings
var names = []; //creates an empty array
var values = [1,2,]; //AVOID! Creates an array with 2 or 3 items
var options = [,,,,,]; //AVOID! creates an array with 5 or 6 items
alert(colors.length); //3
alert(names.length); //0
alert(values.length); //2 (FF, Safari, Opera) or 3 (IE)
alert(options.length); //5 (FF, Safari, Opera) or 6 (IE)
var colors = ["red", "blue", "green"]; //creates an array with three strings
colors.length = 2;
alert(colors[2]); //undefined
var colors = ["red", "blue", "green"]; //creates an array with three strings
colors.length = 4;
alert(colors[3]); //undefined
var colors = ["red", "blue", "green"]; //creates an array with three strings
colors[colors.length] = "black"; //add a color
colors[colors.length] = "brown"; //add another color
alert(colors.length); //5
alert(colors[3]); //black
alert(colors[4]); //brown
var colors = ["red", "blue", "green"]; //creates an array with three strings
colors[99] = "black"; //add a color (position 99)
alert(colors.length); //100
var colors = ["red", "blue", "green"]; //creates an array with three strings
alert(colors.toString()); //red,blue,green
alert(colors.valueOf()); //red,blue,green
alert(colors); //red,blue,green
var person1 = {
toLocaleString : function () {
return "Nikolaos";
},
toString : function() {
return "Nicholas";
}
};
var person2 = {
toLocaleString : function () {
return "Grigorios";
},
toString : function() {
return "Greg";
}
};
var people = [person1, person2];
alert(people); //Nicholas,Greg
alert(people.toString()); //Nicholas,Greg
alert(people.toLocaleString()); //Nikolaos,Grigorios
var colors = new Array(); //create an array
var count = colors.push("red", "green"); //push two items
alert(count); //2
count = colors.push("black"); //push another item on
alert(count); //3
var item = colors.pop(); //get the last item
alert(item); //"black"
alert(colors.length); //2
var colors = ["red", "blue"];
colors.push("brown"); //add another item
colors[3] = "black"; //add an item
alert(colors.length); //4
var item = colors.pop(); //get the last item
alert(item); //"black"
var colors = new Array(); //create an array
var count = colors.push("red", "green"); //push two items
alert(count); //2
count = colors.push("black"); //push another item on
alert(count); //3
var item = colors.shift(); //get the first item
alert(item); //"red"
alert(colors.length); //2
var colors = new Array(); //create an array
var count = colors.unshift("red", "green"); //push two items
alert(count); //2
count = colors.unshift("black"); //push another item on
alert(count); //3
var item = colors.pop(); //get the first item
alert(item); //"green"
alert(colors.length); //2
var values = [1, 2, 3, 4, 5];
values.reverse();
alert(values); //5,4,3,2,1
var values = [0, 1, 5, 10, 15];
values.sort();
alert(values); //0,1,10,15,5
function compare(value1, value2) {
if (value1 < value2) {
return -1;
} else if (value1 > value2) {
return 1;
} else {
return 0;
}
}
var values = [0, 1, 5, 10, 15];
values.sort(compare);
alert(values); //0,1,5,10,15
function compare(value1, value2) {
if (value1 < value2) {
return 1;
} else if (value1 > value2) {
return -1;
} else {
return 0;
}
}
var values = [0, 1, 5, 10, 15];
values.sort(compare);
alert(values); //15,10,5,1,0
var colors = ["red", "green", "blue"];
alert(colors.join(",")); //red,green,blue
alert(colors.join("||")); //red||green||blue
var colors = ["red", "green", "blue", "yellow", "purple"];
var colors2 = colors.slice(1);
var colors3 = colors.slice(1,4);
alert(colors2); //green,blue,yellow,purple
alert(colors3); //green,blue,yellow
var colors = ["red", "green", "blue"];
var removed = colors.splice(0,1); //remove the first item
alert(colors); //green,blue
alert(removed); //red - one item array
removed = colors.splice(1, 0, "yellow", "orange"); //insert two items at position 1
alert(colors); //green,yellow,orange,blue
alert(removed); //empty array
removed = colors.splice(1, 1, "red", "purple"); //insert two values, remove one
alert(colors); //green,red,purple,orange,blue
alert(removed); //yellow - one item array
var numbers = [1,2,3,4,5,4,3,2,1];
alert(numbers.indexOf(4)); //3
alert(numbers.lastIndexOf(4)); //5
alert(numbers.indexOf(4, 4)); //5
alert(numbers.lastIndexOf(4, 4)); //3
var person = { name: "Nicholas" };
var people = [{ name: "Nicholas" }];
var morePeople = [person];
alert(people.indexOf(person)); //-1
alert(morePeople.indexOf(person)); //0
var numbers = [1,2,3,4,5,4,3,2,1];
var filterResult = numbers.filter(function(item, index, array){
return (item > 2);
});
alert(filterResult); //[3,4,5,4,3]
var numbers = [1,2,3,4,5,4,3,2,1];
var mapResult = numbers.map(function(item, index, array){
return item * 2;
});
alert(mapResult); //[2,4,6,8,10,8,6,4,2]
var values = [1,2,3,4,5];
var sum = values.reduce(function(prev, cur, index, array){
return prev + cur;
});
alert(sum);
Date类型
//Date.now() is in ECMAScript 5
//Prior to that, use +new Date()
var now = (typeof Date.now == "function" ? Date.now() : +new Date());
alert("Right now: " + now);
var now = new Date();
alert(now);
var someDate = new Date(Date.parse("May 25, 2004"));
alert(someDate);
//January 1, 2000 at midnight
var y2k = new Date(Date.UTC(2000, 0));
alert(y2k.toUTCString());
//May 5, 2005 at 5:55:55 PM GMT
var allFives = new Date(Date.UTC(2005, 4, 5, 17, 55, 55));
alert(allFives.toUTCString());
var date1 = new Date(2007, 0, 1); //January 1, 2007
var date2 = new Date(2007, 1, 1); //February 1, 2007
alert(date1 < date2); //true
alert(date1 > date2); //false