Question

I heard that when i use jQuery.ajax and sending data as object – it automatically – escapes the chars.

where does it written ?
I didnt find it in Documentation

is it true ?

Answer 1

Inside the source code, a local function add is defined:

add = function( key, value ) {
   value = jQuery.isFunction( value ) ? value() : value;
   s[ s.length ] = encodeURIComponent( key ) + "=" + encodeURIComponent( value );
};

This function prepares any input by escaping the special characters. When an object is passed as an argument, the buildParams method is invoked, passing the just-defined add function:

for ( var prefix in a ) {
   buildParams( prefix, a[ prefix ], traditional, add );
}

Inside the recursive function buildParams, the add method is invoked for each object-parameter. The flavours differ, but are generally in the following format:

add( prefix, obj );

---

Relevant code, derived from the source code:

    // Serialize an array of form elements or a set of
    // key/values into a query string
    param: function( a, traditional ) {
        var s = [],
            add = function( key, value ) {
                // If value is a function, invoke it and return its value
                value = jQuery.isFunction( value ) ? value() : value;
                s[ s.length ] = encodeURIComponent( key ) + "=" + encodeURIComponent( value );
            };

        // Set traditional to true for jQuery <= 1.3.2 behavior.
        if ( traditional === undefined ) {
            traditional = jQuery.ajaxSettings.traditional;
        }

        // If an array was passed in, assume that it is an array of form elements.
        if ( jQuery.isArray( a ) || ( a.jquery && !jQuery.isPlainObject( a ) ) ) {
            // Serialize the form elements
            jQuery.each( a, function() {
                add( this.name, this.value );
            });

        } else {
            // If traditional, encode the "old" way (the way 1.3.2 or older
            // did it), otherwise encode params recursively.
            for ( var prefix in a ) {
                buildParams( prefix, a[ prefix ], traditional, add );
            }
        }

        // Return the resulting serialization
        return s.join( "&" ).replace( r20, "+" );
    }
});

function buildParams( prefix, obj, traditional, add ) {
    if ( jQuery.isArray( obj ) ) {
        // Serialize array item.
        jQuery.each( obj, function( i, v ) {
            if ( traditional || rbracket.test( prefix ) ) {
                // Treat each array item as a scalar.
                add( prefix, v );

            } else {
                // If array item is non-scalar (array or object), encode its
                // numeric index to resolve deserialization ambiguity issues.
                // Note that rack (as of 1.0.0) can't currently deserialize
                // nested arrays properly, and attempting to do so may cause
                // a server error. Possible fixes are to modify rack's
                // deserialization algorithm or to provide an option or flag
                // to force array serialization to be shallow.
                buildParams( prefix + "[" + ( typeof v === "object" || jQuery.isArray(v) ? i : "" ) + "]", v, traditional, add );
            }
        });

    } else if ( !traditional && obj != null && typeof obj === "object" ) {
        // Serialize object item.
        for ( var name in obj ) {
            buildParams( prefix + "[" + name + "]", obj[ name ], traditional, add );
        }

    } else {
        // Serialize scalar item.
        add( prefix, obj );
    }
}