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小編給大家分享一下JavaScript正則表達式校驗與遞歸函數實際應用的示例分析,相信大部分人都還不怎么了解,因此分享這篇文章給大家參考一下,希望大家閱讀完這篇文章后大有收獲,下面讓我們一起去了解一下吧!
JS遞歸函數(菲波那切數列)
實例解析:
一組數字: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); } }
正則表達式檢驗
//校驗是否全由數字組成 function isDigit(s) { var patrn=/^[0-9]{1,20}$/; if (!patrn.exec(s)) return false return true } //校驗登錄名:只能輸入5-20個以字母開頭、可帶數字、“_”、“.”的字串 function isRegisterUserName(s) { var patrn=/^[a-zA-Z]{1}([a-zA-Z0-9]|[._]){4,19}$/; if (!patrn.exec(s)) return false return true } //校驗用戶姓名:只能輸入1-30個以字母開頭的字串 function isTrueName(s) { var patrn=/^[a-zA-Z]{1,30}$/; if (!patrn.exec(s)) return false return true } //校驗密碼:只能輸入6-20個字母、數字、下劃線 function isPasswd(s) { var patrn=/^(\w){6,20}$/; if (!patrn.exec(s)) return false return true } //校驗普通電話、傳真號碼:可以“+”開頭,除數字外,可含有“-” function isTel(s) { //var patrn=/^[+]{0,1}(\d){1,3}[ ]?([-]?(\d){1,12})+$/; var patrn=/^[+]{0,1}(\d){1,3}[ ]?([-]?((\d)|[ ]){1,12})+$/; if (!patrn.exec(s)) return false return true } //校驗手機號碼:必須以數字開頭,除數字外,可含有“-” function isMobil(s) { var patrn=/^[+]{0,1}(\d){1,3}[ ]?([-]?((\d)|[ ]){1,12})+$/; if (!patrn.exec(s)) return false return true } //校驗郵政編碼 function isPostalCode(s) { //var patrn=/^[a-zA-Z0-9]{3,12}$/; var patrn=/^[a-zA-Z0-9 ]{3,12}$/; if (!patrn.exec(s)) return false return true } //校驗搜索關鍵字 function isSearch(s) { var patrn=/^[^`~!@#$%^&*()+=|\\\][\]\{\}:;\'\,.<>/?]{1}[^`~!@$%^&()+=|\\\][\]\{\}:;\'\,.<>?]{0,19}$/; if (!patrn.exec(s)) return false return true } function isIP(s) //by zergling { var patrn=/^[0-9.]{1,20}$/; 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('/'); var the2nd = theStr.lastIndexOf('/'); 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); }
正則表達式應用
"^\\d+$" //非負整數(正整數 + 0) "^[0-9]*[1-9][0-9]*$" //正整數 "^((-\\d+)|(0+))$" //非正整數(負整數 + 0) "^-[0-9]*[1-9][0-9]*$" //負整數 "^-?\\d+$" //整數 "^\\d+(\\.\\d+)?$" //非負浮點數(正浮點數 + 0) "^(([0-9]+\\.[0-9]*[1-9][0-9]*)|([0-9]*[1-9][0-9]*\\.[0-9]+)|([0-9]*[1-9][0-9]*))$" //正浮點數 "^((-\\d+(\\.\\d+)?)|(0+(\\.0+)?))$" //非正浮點數(負浮點數 + 0) "^(-(([0-9]+\\.[0-9]*[1-9][0-9]*)|([0-9]*[1-9][0-9]*\\.[0-9]+)|([0-9]*[1-9][0-9]*)))$" //負浮點數 "^(-?\\d+)(\\.\\d+)?$" //浮點數 "^[A-Za-z]+$" //由26個英文字母組成的字符串 "^[A-Z]+$" //由26個英文字母的大寫組成的字符串 "^[a-z]+$" //由26個英文字母的小寫組成的字符串 "^[A-Za-z0-9]+$" //由數字和26個英文字母組成的字符串 "^\\w+$" //由數字、26個英文字母或者下劃線組成的字符串 "^[\\w-]+(\\.[\\w-]+)*@[\\w-]+(\\.[\\w-]+)+$" //email地址 "^[a-zA-z]+://(\\w+(-\\w+)*)(\\.(\\w+(-\\w+)*))*(\\?\\S*)?$" //url
遞歸函數應用
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