Common simple JavaScript Functions

// Function name: strByteLength
// Function Description: returns the length of a string in bytes.
// Parameter description: string to be checked by str
// Return value: String Length
Function strByteLength (str)
{
Var I, sum;
Sum = 0;
For (I = 0; I <str. length; I ++)
{
If (str. charCodeAt (I)> = 0) & (str. charCodeAt (I) <= 255 ))
Sum = sum + 1;
Else
Sum = sum + 2;
}
Return sum;
}
// Function name: fucCheckLength
// Function Description: Check whether the form meets the specified length.
// Parameter description: The form object to be checked by obj
// Name Object name
// Length
// Return value: true (yes) or false (NO)
Function fucCheckLength (obj, name, length)
{
Var I, sum;
Sum = 0;
Var strTemp = obj. value;
For (I = 0; I <strTemp. length; I ++)
{
If (strTemp. charCodeAt (I)> = 0) & (strTemp. charCodeAt (I) <= 255 ))
Sum = sum + 1;
Else
Sum = sum + 2;
}
If (sum <= length)
{
Return true;
}
Else
{
Alert (name + "exceeds the specified length! The maximum length is "+ length +" characters (two Chinese characters )! ");
Obj. focus ();
Return false;
}
}
// Check whether the email is valid
Function checkEmail (Object)
{
Var pattern =/^ [.-_ A-Za-z0-9] + @ ([-_ A-Za-z0-9] + \.) + [A-Za-z0-9] {2, 3} $ /;
Var strValue = Object. value;
If (strValue. match (pattern) = null ){
Alert ("Email is invalid. Please enter it again! ");
Object. focus ();
Return false;
} Else {
Return true;
}
}
// Return the null interval function
Function Jtrim (str ){
Var I = 0;
Var len = str. length;
If (str = "") return (str );
J = len-1;
Flagbegin = true;
Flagend = true;
While (flagbegin = true & I <len ){
If (str. charAt (I) = ""){
I = I + 1;
Flagbegin = true;
} Else {
Flagbegin = false;
}
}
While (flagend = true & j> = 0 ){
If (str. charAt (j) = ""){
J = J-1;
Flagend = true;
} Else {
Flagend = false;
}
}
If (I> j) return ("")
Trimstr = str. substring (I, j + 1 );
Return trimstr;
}
// Function name: JtrimCn
// Function Description: Remove spaces before and after the string [including Chinese spaces]
// Parameter description: string to be operated by str
// Return value: the string with leading and trailing spaces [including Chinese spaces] is deleted.
Function JtrimCn (str ){
Var I = 0;
If (str = null | str = undefined ){
Return "";
}
Var len = str. length;
If (str = ""){
Return (str );
}
J = len-1;
Flagbegin = true;
Flagend = true;
While (flagbegin = true & I <len ){
If (str. charAt (I) = "" | str. charAt (I) = ""){
I = I + 1;
Flagbegin = true;
} Else {
Flagbegin = false;
}
}
While (flagend = true & j> = 0 ){
If (str. charAt (j) = "" | str. charAt (j) = ""){
J = J-1;
Flagend = true;
} Else {
Flagend = false;
}
}
If (I> j ){
Return ("")
}
Var trimstr = str. substring (I, j + 1 );
Return trimstr;
}
// 0-9, A-Z, a-z standard character judgment
Function isChar (Str ){
Var regu = "^ ([0-9a-zA-Z] +) $ ";
Var re = new RegExp (regu );
If (Str. search (re )! =-1 ){
Return true;
}
Return false;
}
// Determine whether the number is correct.
Function IsNum (Str ){
Var regu = "^ ([0-9] +) $ ";
Var re = new RegExp (regu );
If (Str. search (re )! =-1)
Return true;
{
Return false;
}
}
// Function name: funcIsNotEmpty
// Function Description: Check whether the string is empty
// Parameter description: str string
// Return value: true: Not empty; false: NULL
Function funcIsNotEmpty (str ){
Var s =/\ S /;
If (str = null ){
Return false;
}
Return s. test (str );
}
// Function name: fucCheckLength
// Function Description: Check whether the form meets the specified length.
// Parameter description: value of the form object to be checked by objValue
// Name Object name
// Min length of minLen
// MaxLen maximum length
// Return value: true (yes) or false (NO)
Function fucCheckLengthB (objValue, minLen, maxLen)
{
Var I, sum;
Sum = 0;
Var strTemp = objValue;
For (I = 0; I <strTemp. length; I ++)
{
If (strTemp. charCodeAt (I)> = 0) & (strTemp. charCodeAt (I) <= 255 ))
Sum = sum + 1;
Else
Sum = sum + 2;
}
If (sum <= maxLen & sum> = minLen)
{
Return true;
}
Else
{
Return false;
}
}
// SDate1 and sDate2 are in 2002-12-18 format
Function funDateDiff (sDate1, sDate2 ){
Var aDate, oDate1, oDate2, iDays;
ADate = sDate1.split ("-");
// Convert to the 12-18-2002 format
ODate1 = new Date (aDate [1] + '-' + aDate [2] + '-' + aDate [0]);
ADate = sDate2.split ("-");
ODate2 = new Date (aDate [1] + '-' + aDate [2] + '-' + aDate [0]);
// Converts the difference in milliseconds to the number of days
IDays = parseInt (Math. abs (oDate1-oDate2)/1000/60/60/24 );
// If the start time is earlier than the end time
If (sDate1> sDate2)
{
Return (-1 * iDays );
}
Return iDays;
}
// Check whether the email is valid
Function funcCheckEmail (strValue)
{
Var pattern =/^ [.-_ A-Za-z0-9] + @ ([-_ A-Za-z0-9] + \.) + [A-Za-z0-9] {2, 3} $ /;
If (strValue. match (pattern) = null ){
Return false;
} Else {
Return true;
}
}
// Function name: fucCheckMaxLength
// Function Description: Check whether the form meets the specified length.
// Parameter description: value of the form object to be checked by objValue
// Name object Value
// MaxLen maximum length
// Return value: true (yes) or false (NO)
Function fucCheckMaxLength (objValue, maxLen)
{
Return fucCheckLengthB (objValue, 0, maxLen );
}
// Function name: fucCheckMaxLength
// Function Description: Check whether the specified object value complies with the specified length.
// Parameter description: value of the form object to be checked by objValue
// Name object
// MaxLen maximum length
// Return value: true (yes) or false (NO)
Function fucCheckObjMaxLength (obj, maxLen)
{
If (obj = null ){
Return false;
}
Return fucCheckLengthB (obj. value, 0, maxLen );
}
// Function name: funcCheckInvalidChar
// Function Description: determines whether the specified field contains invalid characters. <>
// Parameter description: The form object to be checked by obj
// Return value: true (NO) or false (yes)
Function funcCheckInvalidChar (obj)
{
If (obj = null | obj. value = "")
{
Return true;
}
// Alert (obj. value );
Var pattern =/[<>]/;
If (pattern. test (obj. value )){
Return false;
} Else {
Return true;
}
}
/**
* Determines whether the maximum length of the object with the specified ID is correct.
* Param: objId Object ID
* MaxLength maximum length
* Return: true is correct. false is incorrect.
*/
Function lengthMaxCheckMsg (objId, maxLength, objName, needFocus, showMsg ){
// Check personal information
Var obj = document. getElementById (objId );
If (! FucCheckObjMaxLength (obj, maxLength )){
If (showMsg = null | showMsg = ""){
Alert (objName + "up to" + (maxLength/2) + "Chinese characters (or" + maxLength + "English digit )");
} Else {
Alert (showMsg );
}
If (needFocus ){
Obj. focus ();
}
Return false;
}
Return true;
}
/**
* Determines whether the specified ID object contains invalid characters.
* Param: objId Object ID
* Name of the objName object
* Does the needFocus need to be set?
* Error message displayed by showMsg
* Return: true is correct. false is incorrect.
*/
Function invalidCharCheckMsg (objId, objName, needFocus, showMsg ){
// Check personal information
Var obj = document. getElementById (objId );
If (! FuncCheckInvalidChar (obj )){
If (showMsg = null | showMsg = ""){
Alert (objName + 'cannot contain "<" or "> "');
} Else {
Alert (showMsg );
}
If (needFocus ){
Obj. focus ();
}
Return false;
}
Return true;
}
/**
* Determines whether the object of the specified ID is null.
* Param: objId Object ID
* Name of the objName object
* Does the needFocus need to be set?
* Error message displayed by showMsg
* Return: true is not null, and false is null.
*/
Function emptyCheckMsg (objId, objName, needFocus, showMsg ){
// Check personal information
Var obj = document. getElementById (objId );
If (! FuncIsNotEmpty (obj. value )){
If (showMsg = null | showMsg = ""){
Alert (objName + 'cannot be blank! ');
} Else {
Alert (showMsg );
}
If (needFocus ){
Obj. focus ();
}
Return false;
}
Return true;
}
/* Date calculation functions
* Date 2007-01-01
* Cnt 1 or-1
* Return 2007-01-02
*/
Function getDate (date, cnt ){
If (date. length! = 10 ){
Return "";
}
Var dateArray = date. split ("-")
If (dateArray = null ){
Return "";
}
Var temDate = new Date (dateArray [0], dateArray [1]-1, dateArray [2]);
Var newDate = Date. UTC (temDate. getYear (), temDate. getMonth (), temDate. getDate ())
NewDate = newDate + (cnt * 24x60*60*1000 );
NewDate = new Date (newDate );
Var month = newDate. getMonth () + 1;
Var day = newDate. getDate ();
If (Number (month) <10)
Month = "0" + month;
If (Number (day) <10)
Day = "0" + day;
Var retDate = newDate. getYear () + "-" + month + "-" + day;
Return retDate;
}