Introduction to vbscript functions for beginners. Learn vbscript functions basics

A Function procedure is a series of VBScript statements enclosed by the Function and End Function statements. A Function procedure is similar to a Sub procedure, but can also return a value. A Function procedure can take arguments (constants, variables, or expressions that are passed to it by a calling procedure). If a Function procedure has no arguments, its Function statement must include an empty set of parentheses. A Function returns a value by assigning a value to its name in one or more statements of the procedure. The return type of a Function is always a Variant.[msdn.microsoft]
Here is a syntax for none-parameterized function procedure:
function userName()
userName="Clay"
end function. This function remembers user name. You can use this function any number of times in your program and you change it once in here to maintain. Use userName() to call this function. eg; document.write("The usre name is: "& userName()).
Here is a syntax for parameterized function:
Function total(price)
  dim tax
  tax=price*.09
  total=price+tax
end Function. The price value is provided when calling the function. eg; document.write("Total price is: " & total(50)).

The following example is function procedure that takes users first name and last name. The values are genetically provided by the user using input box. The function returns users full name on message box.
<html>
<head>
<script language="vbscript">
function userName(first,last)
  userName=first&" "&last
end function
</script>
</head>
<body>
<script language="vbscript">
  dim firstName
  dim lastName
  firstName=inputbox("Enter your first name")
  lastName=inputbox("Enter your last name")
  msgbox("Your full name is: "& userName(firstName,lastName))
</script>
</body>
</html>
This example has two scripts. The function in the head section of the document and the statements in the body of the document. The function simply takes two parameters, first & last and concatenates into function return value userName. The second part declares two variables, firstName and lastName then prompts input boxes. The typed value are stored in these two variables. The two values are passed into the function which prompts back the concatenation of the two values.

VB Script Predefined Functions

These are built-in VBScript functions. All you have to do is pass proper values to these function and they will respond as they built for.

String Functions Function Decriptions Function Example

Asc Returns the ASCII character code for the first character of a string. document.write(ASC ("ABC")). returns: 65

Chr Returns the corresponding character of passed ASCII code number. document.write((Chr(65))). returns: A

LCase Converts all the characters to lowercase. document.write(lcase("CASE")). returns: case

UCase Converts all the characters to upper case. document.write(Ucase("Case")). returns: CASE

Left Returns specified number of characters starting from left. document.write(left("language",3)). returns: lan

Right Returns specified number of characters staring from right. document.write(Right("language")). returns: age

LTrim Removes all the leading spaces from the string. document.write(LTrim("far ")). returns: far, with no spaces

RTrim Removes all the trailing spaces rom the string. document.write(RTrim(" far")). returns: far, with no spaces

Trim Returns the string argument, with leading and trailing spaced removed. document.write(Trim(" mid ")). returns: mid, with no spaces.

Val Returns number value of a string. Stops as soon it hits string char. document.write(Val("22 Maple st.")). returns: 22

String Takes a number and character code argument and returns the character, repeated a number of times: document.write(String(3,80)). returns: BBB

Date Functions

Now() Returns current system date and time. document.write(now()). returns: 8/2/02 10:46:33 AM ->with current date & time

Date Returns the current system date in month, day, year format. document.write(date()). returns: 8/2/02 ->with current date

Time Returns the current system time. document.write(Time()). returns: 10:11:36 AM ->with current time.

Day Returns the day of the month. document.write(Day(date)). returns: 9 ->with current day number.

Month Returns the month of the year. document.write(Month(date)). returns: 9 ->with current month number.

MonthName Returns the name of the specified month. document.write(MonthName(9)). returns: September

WeekDay Returns number representing the day of the week. document.write(WeekDay(date)). returns: 6 -> Assuming today is Friday

WeekdayName Returns the name of the specified week day. document.write(WeekdayName(6)). returns: Friday

DateAdd Adds the specified date or time value to specified date. document.write(DateAdd("d","10","6-7-02")). returns: 6/17/02 -> Adds 10 days to specified date. d=day, m=month, y=year, h=hour, n=minute

Hour, Minute, Second Returns the number representing hour, minute, second of the day, hour, or minute. document.write(Hour()). returns: 11 -> Assuming it's the hour is 11.

Timer Returns the number of seconds since 12:00 AM. document.write(Timer). returns: 40055.84 -> at 11:07 AM

TimeSerial Returns the time for a specific hour, minute, and second converted from military clock. document.write(TimeSerial(17,30,05)). returns: 5:30:05 PM.

TimeValue(time) Returns the current system time. document.write(Time(time))returns: 11:18:00 AM -> with current time.

FormatDateTime Returns a formatted date or time. document.write(FormatDateTime(date)). returns: 8/2/02-> with current date.

Number Functions

Abs Returns the absolute value of a number. document.write(Abs(-5)). returns: 5

Int Returns the integer part of a number. document.write(Int(5.567)). returns: 5

Fix Returns the integer part of a number. document.write(fix(5.567)). returns: 5

Sqr Returns square root of a number. document.write(sqr(25)). returns: 5

Sgn Returns 1, 0, or -1 for possitive, zerro or negative number document.write(Sgn(-22)). returns: -1

Sin Returns sine value of a number. document.write(sin(1)). returns: 0.841470984807897

Tan Returns tangent value of a number. document.write(tan(1)). returns: 1.5574077246549

Cos Returns cosine value of a number. document.write(Cos(1)). returns: 0.54030230586814

Rnd Returns random number. document.write(Rnd). returns: 0.7055475 ->Needs some code to randamize.

Hex Returns the hexadecimal value of a number. document.write(Hex(10)). returns: A

Round Returns rounded number. document.write(Round(10.888)). returns: 11

IsNumeric Returns boolean value [true or false] indicates whether is number or not. document.write(IsNumeric(10.888)). returns: True

FormatNumber Returns an expression formatted as a number value. document.write(FormatNumber(1000.1111,2)). returns: 1,000.11

FormatPercent Returns an expression formatted as a percent document.write(FormatPercent(.22)). returns: 22.00%

FormatCurrency Returns an expression formatted as a currency value. document.write(FormatCurrency(10.888)). returns: $10.89

Other Functions

MsgBox Returns dialog box with specified expression or arguments. msgbox"Hello World" returns: Hello World -> On dialog box.

Sub Procedures

If statement

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