[Octane]

Ну открываем dev-версию jQuery 1.7.2 и находим метод load начиная со строки 7126:

load: function( url, params, callback ) {
		if ( typeof url !== "string" && _load ) {
			return _load.apply( this, arguments );

		// Don't do a request if no elements are being requested
		} else if ( !this.length ) {
			return this;
		}
*!*
		var off = url.indexOf( " " );
		if ( off >= 0 ) {
			var selector = url.slice( off, url.length );
			url = url.slice( 0, off );
		}
*/!*
		// Default to a GET request
		var type = "GET";

		// If the second parameter was provided
		if ( params ) {
			// If it's a function
			if ( jQuery.isFunction( params ) ) {
				// We assume that it's the callback
				callback = params;
				params = undefined;

			// Otherwise, build a param string
			} else if ( typeof params === "object" ) {
				params = jQuery.param( params, jQuery.ajaxSettings.traditional );
				type = "POST";
			}
		}

		var self = this;

		// Request the remote document
		jQuery.ajax({
			url: url,
			type: type,
			dataType: "html",
			data: params,
			// Complete callback (responseText is used internally)
			complete: function( jqXHR, status, responseText ) {
				// Store the response as specified by the jqXHR object
				responseText = jqXHR.responseText;
				// If successful, inject the HTML into all the matched elements
				if ( jqXHR.isResolved() ) {
					// #4825: Get the actual response in case
					// a dataFilter is present in ajaxSettings
					jqXHR.done(function( r ) {
						responseText = r;
					});
*!*
					// See if a selector was specified
					self.html( selector ?
						// Create a dummy div to hold the results
						jQuery("<div>")
							// inject the contents of the document in, removing the scripts
							// to avoid any 'Permission Denied' errors in IE
							.append(responseText.replace(rscript, ""))

							// Locate the specified elements
							.find(selector) :

						// If not, just inject the full result
						responseText );
				}
*/!*
				if ( callback ) {
					self.each( callback, [ responseText, status, jqXHR ] );
				}
			}
		});

		return this;
	},

красным выделено то, что реализует нужный вам функционал на основе $.ajax.

Что-то выделение глючит, второй блок на пару строк вверх надо поднять…