Purpose: Checks whether a value is an integer. The value can be of any type but must be declared in case of a variable or object field.

Return Values: Returns true if and only if value is of type integer, otherwise false.

Example:

heitml input:	resulting output:
<? isinteger(128)>	true
<? isinteger(128.39)>	false
<? isinteger("256")>	false
<? isinteger("256.42")>	false
<? isinteger(0)>	true