Common functions of javascript

Common functions of javascript

(1)AlertFunction: displays a warning dialog box, including an OK button.

(2)ConfirmFunction: A confirmation dialog box is displayed, including the OK and Cancel buttons.

(3)EscapeFunction: converts a character to a Unicode code.

(4)EvalFunction: calculates the result of an expression.

    eval("x=10;y=20;document.write(x*y)");    document.write(eval("2+2"));    var x=10;    document.write(eval(x+17));

The eval function can execute strings as javascript code, but this method is very violent and will affect the efficiency of javascript code. It is best to avoid using

(5)IsNaNFunction: test whether (true) No (false) is not a number.

(6)ParseFloatFunction: converts a string to a numeric value.

(7)ParseIntFunction: converts a string to an integer (number of digits can be specified ).

(8)PromptFunction: displays an input dialog box, prompting you to wait for user input. For example:

<Scriptlanguage = "javascript"> alert ("input error"); prompt ("enter your name", "name"); // (title, default value) confirm ("OK no! "); </Script>

(9)UnescapeFunction: decodes characters encoded by the escape function.

(10)IsFinite(Number) checks whether a value can be a finite number and returns True or False

(11)IsNaN(String) checks whether a value is not a finite number.

(12)DecodeURI() Is the encoded URI address decoding

(13)DecodeURIComponent() Is decoded by the encoded URI component.

(14)EncodeURI() Encrypt the string as URI

(15)EncodeURIComponent() Encode the string as a URI component