Javascript常用功能

http://www.w3school.com.cn/example/jsrf_examples.asp

1、获取浏览器相关信息

var browser=navigator.appName

var b_version=navigator.appVersion

var version=parseFloat(b_version)

2、使用 for...In 声明来遍历数组内的元素

var mycars = new Array()

mycars[0] = "宝马"

mycars[1] = "奔驰"

mycars[2] = "宾利"

for (x in mycars)

{

document.write(mycars[x] + "<br />")

}

3、创建一个欢迎 cookie

<script type="text/javascript">

function getCookie(c_name)

{

if (document.cookie.length>0)

{

c_start=document.cookie.indexOf(c_name + "=")

if (c_start!=-1)

{

c_start=c_start + c_name.length+1

c_end=document.cookie.indexOf(";",c_start)

if (c_end==-1) c_end=document.cookie.length

return unescape(document.cookie.substring(c_start,c_end))

}

}

return ""

}

function setCookie(c_name,value,expiredays)

{

var exdate=new Date()

exdate.setDate(exdate.getDate()+expiredays)

document.cookie=c_name+ "=" +escape(value)+

((expiredays==null) ? "" : "; expires="+exdate.toGMTString())

}

function checkCookie()

{

username=getCookie('username')

if (username!=null && username!="")

{alert('Welcome again '+username+'!')}

else

{

username=prompt('Please enter your name:',"")

if (username!=null && username!="")

{

setCookie('username',username,365)

}

}

}

</script>

4、简单的计时

function timedMsg()

{

var t=setTimeout("alert('5 秒！')",5000)

}

5、使用计时事件制作的钟表

function startTime()

{

var today=new Date()

var h=today.getHours()

var m=today.getMinutes()

var s=today.getSeconds()

// add a zero in front of numbers<10

m=checkTime(m)

s=checkTime(s)

document.getElementById('txt').innerHTML=h+":"+m+":"+s

t=setTimeout('startTime()',500)

}

6、创建用于对象的模板

function person(firstname,lastname,age,eyecolor)

{

this.firstname=firstname

this.lastname=lastname

this.age=age

this.eyecolor=eyecolor

}

myFather=new person("John","Adams",35,"black")

7、返回字符串的长度

var txt="Hello World!"

document.write(txt.length)

8、为字符串添加样式

var txt="Hello World!"

document.write("<p>Big: " + txt.big() + "</p>")

document.write("<p>Small: " + txt.small() + "</p>")

document.write("<p>Bold: " + txt.bold() + "</p>")

document.write("<p>Italic: " + txt.italics() + "</p>")

document.write("<p>Blink: " + txt.blink() + " (does not work in IE)</p>")

document.write("<p>Fixed: " + txt.fixed() + "</p>")

document.write("<p>Strike: " + txt.strike() + "</p>")

document.write("<p>Fontcolor: " + txt.fontcolor("Red") + "</p>")

document.write("<p>Fontsize: " + txt.fontsize(16) + "</p>")

document.write("<p>Lowercase: " + txt.toLowerCase() + "</p>")

document.write("<p>Uppercase: " + txt.toUpperCase() + "</p>")

document.write("<p>Subscript: " + txt.sub() + "</p>")

document.write("<p>Superscript: " + txt.sup() + "</p>")

document.write("<p>Link: " + txt.link("http://www.w3school.com.cn") + "</p>")

9、查找字符串起始位置

var str="Hello world!"

document.write(str.indexOf("Hello") + "<br />")

10、替换字符串

var str="Visit Microsoft Microsoft Microsoft!"

document.write(str.replace(/Microsoft/,"W3School"))//替换第一个匹配项

document.write(str.replace(/Microsoft/g,"W3School"))//替换所有匹配项

11、合并两个数组

var arr = new Array(3)

arr[0] = "George"

arr[1] = "John"

arr[2] = "Thomas"

var arr2 = new Array(3)

arr2[0] = "James"

arr2[1] = "Adrew"

arr2[2] = "Martin"

document.write(arr.concat(arr2))

12、将数组元素组成字符串

var arr = new Array(3);

arr[0] = "George"

arr[1] = "John"

arr[2] = "Thomas"

document.write(arr.join());//George,John,Thomas

document.write("<br />");

document.write(arr.join("."));//George.John.Thomas

13、数组排序

var arr = new Array(6)

arr[0] = "George"

arr[1] = "John"

arr[2] = "Thomas"

arr[3] = "James"

arr[4] = "Adrew"

arr[5] = "Martin"

document.write(arr + "<br />");//George,John,Thomas,James,Adrew,Martin

document.write(arr.sort());//Adrew,George,James,John,Martin,Thomas