encodeURIComponent

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Resumen

El método encodeURIComponent() codifica un componente URI (Identificador Uniforme de Recursos) al reemplazar cada instancia de ciertos caracteres por una, dos, tres o cuatro secuencias de escape que representan la codificación UTF-8 del carácter (solo serán cuatro secuencias de escape para caracteres compuestos por dos carácteres "sustitutos").

Sintaxis

encodeURIComponent(str);

Parámetros

str
Cadena. Un componente de un URI.

Descripción

encodeURIComponent escapes all characters except the following: alphabetic, decimal digits, - _ . ! ~ * ' ( )

Note that an URIError will be thrown if one attempts to encode a surrogate which is not part of a high-low pair, e.g.,

// high-low pair ok
alert(encodeURIComponent('\uD800\uDFFF'));

// lone high surrogate throws "URIError: malformed URI sequence"
alert(encodeURIComponent('\uD800'));

// lone low surrogate throws "URIError: malformed URI sequence"
alert(encodeURIComponent('\uDFFF')); 

To avoid unexpected requests to the server, you should call encodeURIComponent on any user-entered parameters that will be passed as part of a URI. For example, a user could type "Thyme &time=again" for a variable comment. Not using encodeURIComponent on this variable will give comment=Thyme%20&time=again. Note that the ampersand and the equal sign mark a new key and value pair. So instead of having a POST comment key equal to "Thyme &time=again", you have two POST keys, one equal to "Thyme " and another (time) equal to again.

For application/x-www-form-urlencoded (POST), spaces are to be replaced by '+', so one may wish to follow a encodeURIComponent replacement with an additional replacement of "%20" with "+".

To be more stringent in adhering to RFC 3986 (which reserves !, ', (, ), and *), even though these characters have no formalized URI delimiting uses, the following can be safely used:

function fixedEncodeURIComponent (str) {
  return encodeURIComponent(str).replace(/[!'()]/g, escape).replace(/\*/g, "%2A");
}

Examples

The following example provides the special encoding required within UTF-8 Content-Disposition and Link server response header parameters (e.g., UTF-8 filenames):

var fileName = 'my file(2).txt';
var header = "Content-Disposition: attachment; filename*=UTF-8''" + encodeRFC5987ValueChars(fileName);

console.log(header); 
// logs "Content-Disposition: attachment; filename*=UTF-8''my%20file%282%29.txt"


function encodeRFC5987ValueChars (str) {
    return encodeURIComponent(str).
        // Note that although RFC3986 reserves "!", RFC5987 does not,
        // so we do not need to escape it
        replace(/['()]/g, escape). // i.e., %27 %28 %29
        replace(/\*/g, '%2A').
            // The following are not required for percent-encoding per RFC5987, 
            //  so we can allow for a little better readability over the wire: |`^
            replace(/%(?:7C|60|5E)/g, unescape);
}

Specifications

Specification Status Comment
ECMAScript 3rd Edition. Standard Initial definition.
ECMAScript 5.1 (ECMA-262)
La definición de 'encodeURIComponent' en esta especificación.
Standard
ECMAScript 2015 (6th Edition, ECMA-262)
La definición de 'encodeURIComponent' en esta especificación.
Standard

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!
Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

See also