Web Standards Programmer's Reference: HTML, CSS, JavaScript®, Perl, Python®, and PHP

C.5. Top-Level Functions

Function	Returns	Description
escape(string)	string	This function encodes the supplied string to make it portable — that is, able to be used in conditions where extended characters are not allowed. To make a string portable, characters other than the following must be encoded: ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 1234567890 @*-_+./ All other characters are converted to their two- or four-digit hexadecimal equivalent (%xx or %uxxxx). For example, a space is converted to hexadecimal %20. Escaped strings are commonly used to embed plain text in URLs and other restricted constructs. Use the unescape() function to translate an encoded string back to its ASCII equivalent.
eval(string)	Value of last statement	This function evaluates the given string and parses it for valid JavaScript code. If valid code is found in the string, the function executes the code and returns the value of the last statement encountered. This function is useful for dynamic scripting — where code is built on the fly by the script.
isFinite(object)	Boolean	This function evaluates the given object and returns true if the object is finite (non-infinity) or false if the object is infinite.
isNaN(object)	Boolean	This function evaluates the given object and returns true if the object cannot be evaluated as a number or false if the object can be evaluated as a number.
number(object)	number or NaN	This function evaluates the given object and parses it to obtain a number. If the object can be evaluated ...