JS递归函数（菲波那切数列）
实例解析：
一组数字:0 1 1 2 3 5 8 13 0 1 2 3 4 5 6 7 sl(0)=0; sl(1)=1; sl(2)=sl(0)+sl(1); sl(3)=sl(1)+sl(2); function sl(i){ if(i==0){ return 0; }else if(i==1){ return 1; }else{ return sl(i-1)+sl(i-2); } }
正则表达式检验
//校验是否全由数字组成 function isDigit(s) { var patrn=https://www.jb51.net/^[0-9]{1,20}$/; if (!patrn.exec(s)) return false return true } //校验登录名：只能输入5-20个以字母开头、可带数字、“_”、“.”的字串 function isRegisterUserName(s) { var patrn=https://www.jb51.net/^[a-zA-Z]{1}([a-zA-Z0-9]|[._]){4,19}$/; if (!patrn.exec(s)) return false return true } //校验用户姓名：只能输入1-30个以字母开头的字串 function isTrueName(s) { var patrn=https://www.jb51.net/^[a-zA-Z]{1,30}$/; if (!patrn.exec(s)) return false return true } //校验密码：只能输入6-20个字母、数字、下划线 function isPasswd(s) { var patrn=https://www.jb51.net/^(\w){6,20}$/; if (!patrn.exec(s)) return false return true } //校验普通电话、传真号码：可以“+”开头，除数字外，可含有“-” function isTel(s) { //var patrn=https://www.jb51.net/^[+]{0,1}(\d){1,3}[ ]?([-]?(\d){1,12})+$/; var patrn=https://www.jb51.net/^[+]{0,1}(\d){1,3}[ ]?([-]?((\d)|[ ]){1,12})+$/; if (!patrn.exec(s)) return false return true } //校验手机号码：必须以数字开头，除数字外，可含有“-” function isMobil(s) { var patrn=https://www.jb51.net/^[+]{0,1}(\d){1,3}[ ]?([-]?((\d)|[ ]){1,12})+$/; if (!patrn.exec(s)) return false return true } //校验邮政编码 function isPostalCode(s) { //var patrn=https://www.jb51.net/^[a-zA-Z0-9]{3,12}$/; var patrn=https://www.jb51.net/^[a-zA-Z0-9 ]{3,12}$/; if (!patrn.exec(s)) return false return true } //校验搜索关键字 function isSearch(s) { var patrn=https://www.jb51.net/^[^`~!@#$%^&*()+=|\\\][\]\{\}:;\'\,.<>/?]{1}[^`~!@$%^&()+=|\\\][\]\{\}:;\'\,.<>?]{0,19}$/; if (!patrn.exec(s)) return false return true } function isIP(s) //by zergling { var patrn=https://www.jb51.net/^[0-9.]{1,20}$/; if (!patrn.exec(s)) return false return true } * FUNCTION: isBetween * PARAMETERS: val AS any value * lo AS Lower limit to check * hi AS Higher limit to check * CALLS: NOTHING * RETURNS: TRUE if val is between lo and hi both inclusive, otherwise false. function isBetween (val, lo, hi) { if ((val < lo) || (val > hi)) { return(false); } else { return(true); } } * FUNCTION: isDate checks a valid date * PARAMETERS: theStr AS String * CALLS: isBetween, isInt * RETURNS: TRUE if theStr is a valid date otherwise false. function isDate (theStr) { var the1st = theStr.indexOf('-'); var the2nd = theStr.lastIndexOf('-'); if (the1st == the2nd) { return(false); } else { var y = theStr.substring(0,the1st); var m = theStr.substring(the1st+1,the2nd); var d = theStr.substring(the2nd+1,theStr.length); var maxDays = 31; if (isInt(m)==false || isInt(d)==false || isInt(y)==false) { return(false); } else if (y.length < 4) { return(false); } else if (!isBetween (m, 1, 12)) { return(false); } else if (m==4 || m==6 || m==9 || m==11) maxDays = 30; else if (m==2) { if (y % 4 > 0) maxDays = 28; else if (y % 100 == 0 && y % 400 > 0) maxDays = 28; else maxDays = 29; } if (isBetween(d, 1, maxDays) == false) { return(false); } else { return(true); } } } * FUNCTION: isEuDate checks a valid date in British format * PARAMETERS: theStr AS String * CALLS: isBetween, isInt * RETURNS: TRUE if theStr is a valid date otherwise false. function isEuDate (theStr) { if (isBetween(theStr.length, 8, 10) == false) { return(false); } else { var the1st = theStr.indexOf('https://www.jb51.net/'); var the2nd = theStr.lastIndexOf('https://www.jb51.net/'); if (the1st == the2nd) { return(false); } else { var m = theStr.substring(the1st+1,the2nd); var d = theStr.substring(0,the1st); var y = theStr.substring(the2nd+1,theStr.length); var maxDays = 31; if (isInt(m)==false || isInt(d)==false || isInt(y)==false) { return(false); } else if (y.length < 4) { return(false); } else if (isBetween (m, 1, 12) == false) { return(false); } else if (m==4 || m==6 || m==9 || m==11) maxDays = 30; else if (m==2) { if (y % 4 > 0) maxDays = 28; else if (y % 100 == 0 && y % 400 > 0) maxDays = 28; else maxDays = 29; } if (isBetween(d, 1, maxDays) == false) { return(false); } else { return(true); } } } } * FUNCTION: Compare Date! Which is the latest! * PARAMETERS: lessDate,moreDate AS String * CALLS: isDate,isBetween * RETURNS: TRUE if lessDate<moreDate function isComdate (lessDate , moreDate) { if (!isDate(lessDate)) { return(false);} if (!isDate(moreDate)) { return(false);} var less1st = lessDate.indexOf('-'); var less2nd = lessDate.lastIndexOf('-'); var more1st = moreDate.indexOf('-'); var more2nd = moreDate.lastIndexOf('-'); var lessy = lessDate.substring(0,less1st); var lessm = lessDate.substring(less1st+1,less2nd); var lessd = lessDate.substring(less2nd+1,lessDate.length); var morey = moreDate.substring(0,more1st); var morem = moreDate.substring(more1st+1,more2nd); var mored = moreDate.substring(more2nd+1,moreDate.length); var Date1 = new Date(lessy,lessm,lessd); var Date2 = new Date(morey,morem,mored); if (Date1>Date2) { return(false);} return(true); } * FUNCTION isEmpty checks if the parameter is empty or null * PARAMETER str AS String function isEmpty (str) { if ((str==null)||(str.length==0)) return true; else return(false); } * FUNCTION: isInt * PARAMETER: theStr AS String * RETURNS: TRUE if the passed parameter is an integer, otherwise FALSE * CALLS: isDigit function isInt (theStr) { var flag = true; if (isEmpty(theStr)) { flag=false; } else { for (var i=0; i<theStr.length; i++) { if (isDigit(theStr.substring(i,i+1)) == false) { flag = false; break; } } } return(flag); } * FUNCTION: isReal * PARAMETER: heStr AS String decLen AS Integer (how many digits after period) * RETURNS: TRUE if theStr is a float, otherwise FALSE * CALLS: isInt function isReal (theStr, decLen) { var dot1st = theStr.indexOf('.'); var dot2nd = theStr.lastIndexOf('.'); var OK = true; if (isEmpty(theStr)) return false; if (dot1st == -1) { if (!isInt(theStr)) return(false); else return(true); } else if (dot1st != dot2nd) return (false); else if (dot1st==0) return (false); else { var intPart = theStr.substring(0, dot1st); var decPart = theStr.substring(dot2nd+1); if (decPart.length > decLen) return(false); else if (!isInt(intPart) || !isInt(decPart)) return (false); else if (isEmpty(decPart)) return (false); else return(true); } } * FUNCTION: isEmail * PARAMETER: String (Email Address) * RETURNS: TRUE if the String is a valid Email address * FALSE if the passed string is not a valid Email Address * EMAIL FORMAT: AnyName@EmailServer e.g; webmaster@hotmail.com * @ sign can appear only once in the email address. function isEmail (theStr) { var atIndex = theStr.indexOf('@'); var dotIndex = theStr.indexOf('.', atIndex); var flag = true; theSub = theStr.substring(0, dotIndex+1) if ((atIndex < 1)||(atIndex != theStr.lastIndexOf('@'))||(dotIndex < atIndex + 2)||(theStr.length <= theSub.length)) { return(false); } else { return(true); } } * FUNCTION: newWindow * PARAMETERS: doc -> Document to open in the new window hite -> Height of the new window wide -> Width of the new window bars -> 1-Scroll bars = YES 0-Scroll Bars = NO resize -> 1-Resizable = YES 0-Resizable = NO * CALLS: NONE * RETURNS: New window instance function newWindow (doc, hite, wide, bars, resize) { var winNew="_blank"; var opt="toolbar=0,location=0,directories=0,status=0,menubar=0,"; opt+=("scrollbars="+bars+","); opt+=("resizable="+resize+","); opt+=("width="+wide+","); opt+=("height="+hite); winHandle=window.open(doc,winNew,opt); return; } * FUNCTION: DecimalFormat * PARAMETERS: paramValue -> Field value * CALLS: NONE * RETURNS: Formated string function DecimalFormat (paramValue) { var intPart = parseInt(paramValue); var decPart =parseFloat(paramValue) - intPart; str = ""; if ((decPart == 0) || (decPart == null)) str += (intPart + ".00"); else str += (intPart + decPart); return (str); }
正则表达式应用