JS系统函数

2008-01-29js函数集·字符串(String)1.声明var myString = new String("Every good boy does fine.");var myString = "Every good boy does fine.";2.字符串连接var myString = "Every " + "good boy " + "does fine.";var myString = "Every "; myString += "good boy does fine.";3.截取字符串//截取第6 位开始的字符var myString = "Every good boy does fine.";var section = myString.substring(6); //结果: "good boy does fine."//截取第0 位开始至第10 位为止的字符var myString = "Every good boy does fine.";var section = myString.substring(0,10); //结果: "Every good"//截取从第11 位到倒数第6 位为止的字符var myString = "Every good boy does fine.";var section = myString.slice(11,-6); //结果: "boy does"//从第6 位开始截取长度为4 的字符var myString = "Every good boy does fine.";var section = myString.substr(6,4); //结果: "good"4.转换大小写var myString = "Hello";var lcString = myString.toLowerCase(); //结果: "hello"var ucString = myString.toUpperCase(); //结果: "HELLO"5.字符串比较var aString = "Hello!";var bString = new String("Hello!");if( aString == "Hello!" ){ } //结果: trueif( aString == bString ){ } //结果: trueif( aString === bString ){ } //结果: false (两个对象不同,尽管它们的值相同)6.检索字符串var myString = "hello everybody.";// 如果检索不到会返回-1,检索到的话返回在该串中的起始位置if( myString.indexOf("every") > -1 ){ } //结果: true7.查找替换字符串var myString = "I is your father.";var result = myString.replace("is","am"); //结果: "I am your father."8.特殊字符:\b : 后退符\t : 水平制表符\n : 换行符\v : 垂直制表符\f : 分页符\r : 回车符\" : 双引号\' : 单引号\\ : 反斜杆9.将字符转换成Unicode编码var myString = "hello";var code = myString.charCodeAt(3); //返回"l"的Unicode编码(整型)var char = String.fromCharCode(66); //返回Unicode为66的字符10.将字符串转换成URL编码var myString = "hello all";var code = encodeURI(myString); //结果: "hello%20all"var str = decodeURI(code); //结果: "hello all"//相应的还有: encodeURIComponent() decodeURIComponent()11.将字符串转换成base64编码// base64Encode() base64Decode() 用法同上//-----------------------------------------------------------------------·数字型(Number)1.声明var i = 1;var i = new Number(1);2.字符串与数字间的转换var i = 1;var str = i.toString(); //结果: "1"var str = new String(i); //结果: "1"i = parseInt(str); //结果: 1i = parseFloat(str); //结果: 1.0//注意: parseInt,parseFloat会把一个类似于"32G"的字符串,强制转换成323.判断是否为有效的数字var i = 123; var str = "string";if( typeof i == "number" ){ } //true//某些方法(如:parseInt,parseFloat)会返回一个特殊的值NaN(Not a Number) //请注意第2点中的[注意],此方法不完全适合判断一个字符串是否是数字型!!i = parseInt(str);if( isNaN(i) ){ }4.数字型比较//此知识与[字符串比较]相同5.小数转整数var f = 1.5;var i = Math.round(f); //结果:2 (四舍五入)var i = Math.ceil(f); //结果:2 (返回大于f的最小整数)var i = Math.floor(f); //结果:1 (返回小于f的最大整数)6.格式化显示数字var i = 3.14159;//格式化为两位小数的浮点数var str = i.toFixed(2); //结果: "3.14"//格式化为五位数字的浮点数(从左到右五位数字,不够补零)var str = i.toPrecision(5); //结果: "3.1415"7.X进制数字的转换//不是很懂-.-var i = parseInt("0x1f",16);var i = parseInt(i,10);var i = parseInt("11010011",2);8.随机数//返回0-1之间的任意小数var rnd = Math.random();//返回0-n之间的任意整数(不包括n)var rnd = Math.floor(Math.random() * n)//----------------------------------------------------------------------- ·Math对象1. Math.abs(num) : 返回num的绝对值2. Math.acos(num) : 返回num的反余弦值3. Math.asin(num) : 返回num的反正弦值4. Math.atan(num) : 返回num的反正切值5. Math.atan2(y,x) : 返回y除以x的商的反正切值6. Math.ceil(num) : 返回大于num的最小整数7. Math.cos(num) : 返回num的余弦值8. Math.exp(x) : 返回以自然数为底,x次幂的数9. Math.floor(num) : 返回小于num的最大整数10.Math.log(num) : 返回num的自然对数11.Math.max(num1,num2) : 返回num1和num2中较大的一个12.Math.min(num1,num2) : 返回num1和num2中较小的一个13.Math.pow(x,y) : 返回x的y次方的值14.Math.random() : 返回0到1之间的一个随机数15.Math.round(num) : 返回num四舍五入后的值16.Math.sin(num) : 返回num的正弦值17.Math.sqrt(num) : 返回num的平方根18.Math.tan(num) : 返回num的正切值19.Math.E : 自然数(2.718281828459045)20.Math.LN2 : 2的自然对数(0.6931471805599453)21.Math.LN10 : 10的自然对数(2.302585092994046)22.Math.LOG2E : log 2 为底的自然数(1.4426950408889634)23.Math.LOG10E : log 10 为底的自然数(0.4342944819032518)24.Math.PI : π(3.141592653589793)25.Math.SQRT1_2 : 1/2的平方根(0.7071067811865476)26.Math.SQRT2 : 2的平方根(1.4142135623730951)//----------------------------------------------------------------------- ·日期型(Date)1.声明var myDate = new Date(); //系统当前时间var myDate = new Date(yyyy, mm, dd, hh, mm, ss);var myDate = new Date(yyyy, mm, dd);var myDate = new Date("monthName dd, yyyy hh:mm:ss"); var myDate = new Date("monthName dd, yyyy");var myDate = new Date(epochMilliseconds);2.获取时间的某部份var myDate = new Date();myDate.getYear(); //获取当前年份(2位)myDate.getFullYear(); //获取完整的年份(4位,1970-????) myDate.getMonth(); //获取当前月份(0-11,0代表1月)myDate.getDate(); //获取当前日(1-31)myDate.getDay(); //获取当前星期X(0-6,0代表星期天)myDate.getTime(); //获取当前时间(从1970.1.1开始的毫秒数) myDate.getHours(); //获取当前小时数(0-23)myDate.getMinutes(); //获取当前分钟数(0-59)myDate.getSeconds(); //获取当前秒数(0-59)myDate.getMilliseconds(); //获取当前毫秒数(0-999)myDate.toLocaleDateString(); //获取当前日期myDate.toLocaleTimeString(); //获取当前时间myDate.toLocaleString( ); //获取日期与时间3.计算之前或未来的时间var myDate = new Date();myDate.setDate(myDate.getDate() + 10); //当前时间加10天//类似的方法都基本相同,以set开头,具体参考第2点4.计算两个日期的偏移量var i = daysBetween(beginDate,endDate); //返回天数var i = beginDate.getTimezoneOffset(endDate); //返回分钟数5.检查有效日期//checkDate() 只允许"mm-dd-yyyy"或"mm/dd/yyyy"两种格式的日期if( checkDate("2006-01-01") ){ }//正则表达式(自己写的检查yyyy-mm-dd, yy-mm-dd, yyyy/mm/dd, yy/mm/dd 四种)var r = /^(\d{2}|\d{4})[\/-]\d{1,2}[\/-]\d{1,2}$/;if( r.test( myString ) ){ }//-----------------------------------------------------------------------·数组(Array)1.声明var arr = new Array(); //声明一个空数组var arr = new Array(10); //声明一个10个长度的数组var arr = new Array("Alice", "Fred", "Jean"); //用值初始化数组var arr = ["Alice", "Fred", "Jean"]; //用值初始化数组var arr = [["A","B","C"][1,2,3]]; //声明一个二(多)维数组2.数组的访问arr[0] = "123"; //赋值var str = arr[0]; //获取arr[0][0] = "123"; //多维数组赋值3.数组与字符串间的转换var arr = ["A","B","C","D"]; //声明//数组按分隔符转换成字符串var str = arr.join("|"); //结果: "A|B|C|D"//字符串切割成数组arr = str.split("|");4.遍历数组for( var i=0; i<arr.length; i++ ){ alert(arr[i]); }5.排序var arr = [12,15,8,9];arr.sort(); //结果: 8 9 12 156.组合与分解数组var arr1 = ["A","B","C","D"];var arr2 = ["1","2","3","4"];//奖两个数组组合成一个新的数组var arr = arr1.concat(arr2); //结果: ["A","B","C","D","1","2","3","4"]//将一个数组切成两个数组(参数1:起始索引,参数2:切割长度)var arr3 = arr.splice(1,3); //结果: arr3:["B","C","D"] arr["A","1","2","3","4"]//将一个数组切成两个数组,并在原数组补新值var arr4 = arr.splice(1,3,"AA"); //结果: arr4:["B","C","D"]arr["A","AA","1","2","3","4"]//----------------------------------------------------------------------- ·自定义对象1.声明:function myUser(uid,pwd){this.uid = uid;this.pwd = pwd || "000000"; //默认值this.show = showInfo; //方法}//下面的函数不是自定义对象,是自定义对象的方法.继续看下去就明白了function showInfo(){alert("用户名:" + this.uid + ",密码:" + this.pwd)}2.实例化:var user = new myUser("user","123456");var user = {uid:"user",pwd:"123456"};3.获取与设置alert("用户名是:" + user.uid); //getuser.uid = "newuser"; //setuser.show(); //调用show()方法//----------------------------------------------------------------------- ·变量函数流程控制1.变量var i = 1;var i = 1, str = "hello";2.函数function funName(){//do something.}function funName(param1[,paramX]){//do something.}3.嵌套函数//某种情况,你需要创建一个函数本身所独有的函数.function myFunction(){//do something.privateFunction();function privateFunction(){//do something.}}4.匿名函数var tmp = function(){ alert("only test."); }tmp();5.延迟函数调用var tId = setTimeout("myFun()",1000); //延迟1000毫秒后再调用myFun()函数fucntion myFun(){//do somethingclearTimeout(tId); //销毁对象}6.流程控制if( condition ){ }if( condition ){ } else{ }if( condition ){ } else if( condition ){ } else{ }switch( expression ){case valA : statement; break;case valB : statement; break;default : statement; break;}7.异常捕获try{ expression } catch(e){ } finally{ }//不处理任何异常window.onerror = doNothing;function doNothing(){ return true; }//异常类可用的属性description : 异常描述(IE,NN)fileName : 异常页面URI(NN)lineNumber : 异常行数(NN)message : 异常描述(IE,NN)name : 错误类型(IE,NN)number : 错误代码(IE)//错误信息(兼容所有浏览器)try{ }catch(e){var msg = (e.message) ? e.message : e.description;alert(msg);}8.加快脚本的执行速度-避免使用eval() 函数-避免使用with 关键字-将重复的表达式赋值精简到最小-在较大的对象中使用索引来查找数组-减少document.write() 的使用//-----------------------------------------------------------------------·浏览器特征( navigator )1.浏览器名称//IE : "Microsoft Internet Explorer"//NS : "Netscape"var browserName = navigator.appName;2.浏览器版本bar browserVersion = navigator.appVersion;3.客户端操作系统var isWin = ( erAgent.indexOf("Win") != -1 );var isMac = ( erAgent.indexOf("Mac") != -1 );var isUnix = ( erAgent.indexOf("X11") != -1 );4.判断是否支持某对象,方法,属性//当一个对象,方法,属性未定义时会返回undefined或null等,这些特殊值都是false if( document.images ){ }if( document.getElementById ){ }5.检查浏览器当前语言if( erLanguage ){ var l =erLanguage.toUpperCase(); }6.检查浏览器是否支持Cookiesif( navigator.cookieEnabled ){ }//-----------------------------------------------------------------------·控制浏览器窗口( window )1.设置浏览器的大小window.resizeTo(800, 600); //将浏览器调整到800X600大小window.resizeBy(50, -10); //在原有大小上改变增大或减小窗口大小2.调整浏览器的位置window.moveTo(10, 20); //将浏览器的位置定位到X:10 Y:20window.moveBy(0, 10); //在原有位置上移动位置(偏移量)3.创建一个新的窗口var win = window.open("about.htm","winName","height=300,width=400");alwaysLowered //始终在其它浏览器窗口的后面(NN)alwaysRaised //始终在其它浏览器窗口的前面(NN)channelMode //是否为导航模式(IE)copyhistory //复制历史记录至新开的窗口(NN)dependent //新窗口随打开它的主窗口关闭而关闭(NN)fullscreen //全屏模式(所有相关的工具栏都没有)(IE)location //是否显示地址栏(NN,IE)menubar //是否显示菜单栏(NN,IE)scrollbars //是否显示滚动条(NN,IE)status //是否显示状态栏(NN,IE)toolbar //是否显示工具栏(NN,IE)directories //是否显示链接栏(NN,IE)titlebar //是否显示标题栏(NN)hotkeys //显示菜单快捷键(NN)innerHeight //内容区域的高度(NN)innerWidth //内容区域的宽度(NN)resizable //是否可以调整大小(NN,IE)top //窗口距离桌面上边界的大小(NN,IE)left //窗口距离桌面左边界的大小(NN,IE)height //窗口高度(NN,IE)width //浏览器的宽度4.与新窗口通讯win.focus(); //让新窗口获得焦点win.document.write("abc"); //在新窗口上操作win.document.close(); //结束流操作opener.close();5.模式窗口window.showModalDialog("test.htm",dialogArgs,"param"); //传递对象window.showModelessDialog("test.htm",myFunction,"param"); //传递函数window.dialogArguments //对话框访问父窗口传递过来的对象window.returnValue //父窗口获取对话框返回的值//参数center //窗口居中屏幕dialogHeight //窗口高度dialogWidth //窗口宽度dialogTop //窗口距离屏幕的上边距dialogLeft //窗口距离屏幕的左边距edge //边框风格(raised|sunken)help //显示帮助按钮resizable //是否可以改变窗口大小status //是否显示状态栏<script>function openDialog(myForm) {var result = window.showModalDialog("new.html",myForm,"center");}</script><form action="#" onsubmit="return false"><input type="text" id="txtId"><input type="button" id="btnChk" value="验证是否可用"onclick="openDialog(this.form);"></form>//另一个页面new.html<script>window.dialogArguments.btnChk.enabled = false; //将父窗口中的按钮设置为不可用//do something to check the Id.window.write("用户ID: " + window.dialogArguments.txtId.value + " 可使用!"); //获取文本框的值</script>//-----------------------------------------------------------------------·管理框架网页( frames )1.创建一个框架架构网页<html><frameset rows="50, *"><frame name="header" src="header.html"><frame name="main" src="main.html"></frameset></html>2.访问框架网页window.frames[i]window.frames["frameName"]window.frameNamewindow.frames["frameName"].frames["frameName2"]parent.frames["frameName"]top.frames["frameName"]3.将某一页面定向到某框架<a href="new.html" target="main">location = "new.html";parent.frameName.location.href = "new.html";top.frameName.location = "new.html";4.强制不让其它框架引用某页面if (top != self) {top.location.href = location.href;}5.更改框架的大小document.framesetName.rows = "50,*";document.framesetName.cols = "50,*";6.动态创建框架网页var frag = document.createDocumentFragment( );var newFrame= document.createElement("frame"); newFrame.id = "header"; = "header";newFrame.src="header.html"frag.appendChild(newFrame);newFrame = document.createElement("frame");newFrame.id = "main"; = "main";newFrame.src="main.html"frag.appendChild(newFrame);document.getElementById("masterFrameset").rows = "50,*";//-----------------------------------------------------------------------。