Common JavaScript detection scripts (2)

/* *
* Purpose: Check whether the input string is composed of English letters, numbers, and underscores (_).
* Input: S, string
* Return: If the verification succeeds, true is returned; otherwise, false is returned.
  */
Function Isnumberor_letter (s ){
VaR Regu =   " ^ [0-9a-za-z \ _] + $ " ;
VaR Re =   New Regexp (regu );
If (Re. test (s )) Return   True ;
Else Return   False ;
}

/* *
* Purpose: Check whether the input string consists of only English letters and numbers.
* Input: S, string
* Return: If the verification succeeds, true is returned; otherwise, false is returned.
  */
Function Isnumberorletter (s ){ // Determine whether it is a number or letter
VaR Regu =   " ^ [0-9a-za-z] + $ " ;
VaR Re =   New Regexp (regu );
If (Re. test (s )) Return   True ;
Else   Return   False ;
}

/* *
* Purpose: Check whether the input string consists of only Chinese characters, letters, and numbers.
* Input: value, string
* Return: If the verification succeeds, true is returned; otherwise, false is returned.
  */
Function Ischinaornumborlett (s ){
VaR Regu =   " ^ [0-9a-za-z \ u4e00-\ u9fa5] + $ " ;
VaR Re =   New Regexp (regu );
If (Re. test (s )) Return   True ;
Else   Return   False ;

}

/* *
* Purpose: determine whether it is a date.
* Input: Date: date; FMT: Date Format
* Return: If the verification succeeds, true is returned; otherwise, false is returned.
  */
Function Isdate (date, FMT ){
If (FMT = Null ) FMT = " Yyyymmdd " ;
VaR Yindex = FMT. indexof ( " Yyyy " );
If (Yindex =- 1 ) Return   False ;
VaR Year = Date. substring (yindex, yindex + 4 );
VaR Mindex = FMT. indexof ( " Mm " );
If (Mindex =- 1 ) Return   False ;
VaR Month = Date. substring (mindex, mindex + 2 );
VaR Dindex = FMT. indexof ( " Dd " );
If (Dindex =- 1 ) Return   False ;
VaR Day = Date. substring (dindex, dindex + 2 );
If ( ! Isnumber (year) | Year > " 2100 "   | Year <   " 1900 " ) Return   False ;
If ( ! Isnumber (month) | Month > " 12 "   | Month <   " 01 " ) Return   False ;
If (Day > Getmaxday (year, month) | Day <   " 01 " ) Return   False ;
Return   True ;
}
 
/* *
* Purpose: Obtain the date value of the last day of each month.
* Input: Date: Year; month: Month
* Return: If the verification succeeds, true is returned; otherwise, false is returned.
  */
Function Getmaxday (year, month ){
If (Month = 4 | Month = 6 | Month = 9 | Month = 11 )
Return   " 30 " ;
If (Month = 2 )
If (Year % 4 = 0 && Year % 100 ! = 0   | Year % 400 = 0 )
Return   " 29 " ;
Else
Return   " 28 " ;
Return   " 31 " ;
}

/* *
* Purpose: determines whether character 1 ends with string 2.
* Input: str1: string; str2: contained string
* Return: If the verification succeeds, true is returned; otherwise, false is returned.
  */
Function Islastmatch (str1, str2 ){
VaR Index = Str1.lastindexof (str2 );
If (Str1.length = Index + Str2.length) Return   True ;
Return   False ;
}

/* *
* Purpose: determines whether character 1 starts with string 2.
* Input: str1: string; str2: contained string
* Return: If the verification succeeds, true is returned; otherwise, false is returned.
  */
Function Isfirstmatch (str1, str2 ){
VaR Index = Str1.indexof (str2 );
If (Index = 0 ) Return   True ;
Return   False ;
}

/* *
* Purpose: character 1 is a string containing 2
* Input: str1: string; str2: contained string
* Return: If the verification succeeds, true is returned; otherwise, false is returned.
  */
Function Ismatch (str1, str2 ){
VaR Index = Str1.indexof (str2 );
If (Index =- 1 ) Return   False ;
Return   True ;
}

/* *
* Purpose: Check whether the input start and end dates are correct. The rules are in the correct format for the two dates and end as scheduled> = Start Date
* Input: startdate: Start Date (string), enddate: end date as scheduled (string)
* Return: If the verification succeeds, true is returned; otherwise, false is returned.
  */
Function Checktwodate (startdate, enddate ){
If ( ! Isdate (startdate )){
Alert ( " Incorrect start date! " );
Return   False ;
} Else   If ( ! Isdate (enddate )){
Alert ( " The end date is incorrect! " );
Return   False ;
} Else   If (Startdate > Enddate ){
Alert ( " The start date cannot be later than the end date! " );
Return   False ;
}
Return   True ;
}