General functions of JavaScript

(1) Alert function: Displays a warning dialog box, including an OK button.

(2) Confirm Function: Displays a confirmation dialog box, including OK, Cancel button.

(3) Escape Function: Converts a character to a Unicode code.

(4) eval function: Evaluates the result of an expression.

[JavaScript]View Plaincopyprint?

1. Eval ("X=10;y=20;document.write (x*y)");
2. document.write (eval ("+ +)");
3. var x=10;
4. document.write (eval (x+17));

The eval function can execute strings as JavaScript code, but this approach is violent and affects the efficiency of JavaScript code, and it's best to avoid using

(5) IsNaN function: The test is (true) No (false) is not a number.

(6) parsefloat Function: Converts a string into a numeric form of a character.

(7) parseint Function: Converts a string into an integer number form (can specify a few binary).

(8) prompt function: Displays an input dialog box prompting for user input. For example:

[JavaScript]View Plaincopyprint?

1. <scriptlanguage="JavaScript" >
3. Alert ("input error");
4. Prompt ("Please enter your name","name"); //(title, default)
5. Confirm ("OK no!  ");
7. </script>

(9) unescape function: Decodes characters encoded by the escape function.

(10) isfinite (number) to detect whether a value can be a finite digit, which returns TRUE or False

(11) IsNaN (string) to detect whether a value is not a finite number

(12) decodeURI () Decodes the encoded URI address

(13) decodeuricomponent () Decodes the encoded URI component

(14) encodeURI () to encrypt a string as a URI

(15) encodeURIComponent () encode a string as a URI component

General functions of JavaScript