Is (function)
IsArray(expression)
IsDate(expression)
IsEmpty(expression)
IsNull(expression)
IsNumeric(expression)
IsObject(expression)
Description
The Is functions return TRUE if a variable type corresponds to the function call, FALSE is returned otherwise. The required parameter, expression, is the variable whose type status is being determined.
Example (Basic)
Rem Is Functions Example Dim Children(3), Chef, When TestVariable Children Chef = 1 TestVariable Chef When = Now TestVariable When Sub TestVariable(x) If IsArray(x) Then Print "The variable is an array." ElseIf IsDate(x) Then Print "The variable is a date." ElseIf IsNumeric(x) Then Print "The variable is a number." End If End Sub
Example (JavaScript)
// Is Functions Example var TestVariable=function(x) { if (!Array.isArray) { Array.isArray = function (x) { return Object.prototype.toString.call(x) === "[object Array]"; }; } IsDate = function(x) { return (null != x) && !isNaN(x) && ("undefined" !== typeof x.getDate); }; IsNumeric = function(n) { return !isNaN(parseFloat(n)) && isFinite(n); }; if (Array.isArray(x)) { document.write(("The variable is an array.") + "<br>"); } else if (IsDate(x) ) { document.write(("The variable is a date.") + "<br>"); } else if (IsNumeric(x) ) { document.write(("The variable is a number.") + "<br>"); } } var Children=new Array(3), Chef, When; TestVariable(Children); var Chef = 1; TestVariable(Chef); var When = new Date(); TestVariable(When);
Output
The variable is an array. The variable is a number. The variable is a date.