jQuery 1.0.js

		show: function(){
			this.style.display = this.oldblock ? this.oldblock : "";
			if ( jQuery.css(this,"display") == "none" )
				this.style.display = "block";
		}

jQuery 1.7.js

	show: function( speed, easing, callback ) {
		var elem, display;

		if ( speed || speed === 0 ) {
			return this.animate( genFx("show", 3), speed, easing, callback );

		} else {
			for ( var i = 0, j = this.length; i < j; i++ ) {
				elem = this[ i ];

				if ( elem.style ) {
					display = elem.style.display;

					// Reset the inline display of this element to learn if it is
					// being hidden by cascaded rules or not
					if ( !jQuery._data(elem, "olddisplay") && display === "none" ) {
						display = elem.style.display = "";
					}

					// Set elements which have been overridden with display: none
					// in a stylesheet to whatever the default browser style is
					// for such an element
					if ( display === "" && jQuery.css(elem, "display") === "none" ) {
						jQuery._data( elem, "olddisplay", defaultDisplay(elem.nodeName) );
					}
				}
			}

			// Set the display of most of the elements in a second loop
			// to avoid the constant reflow
			for ( i = 0; i < j; i++ ) {
				elem = this[ i ];

				if ( elem.style ) {
					display = elem.style.display;

					if ( display === "" || display === "none" ) {
						elem.style.display = jQuery._data( elem, "olddisplay" ) || "";
					}
				}
			}

			return this;
		}
	}