source: oceandb/jQuery_Prototype/script/textualzoomcontrol.js @ 115

  function TextualZoomControl() {
  }
  
  TextualZoomControl.prototype = new GControl();

//  Creates a one DIV for each of the buttons and places them in a container
//  DIV which is returned as our control element.
  TextualZoomControl.prototype.initialize = function(map) {
    var container = document.createElement("div");

// "Zoom In" button
    var zoomInDiv = document.createElement("div");
    this.setButtonStyle_(zoomInDiv);
    container.appendChild(zoomInDiv);
    zoomInDiv.appendChild(document.createTextNode("Zoom In"));
    // The "true" argument in the zoomIn() method allows continuous zooming
    GEvent.addDomListener(zoomInDiv, "click", function() {map.zoomIn(null,null,true);} );

// "Zoom Out" button
    var zoomOutDiv = document.createElement("div");
    this.setButtonStyle_(zoomOutDiv);
    zoomOutDiv.style.borderTop = 0+'px';
    container.appendChild(zoomOutDiv);
    zoomOutDiv.appendChild(document.createTextNode("Zoom Out"));
    // The "true" argument in the zoomOut() method allows continuous zooming
    GEvent.addDomListener(zoomOutDiv, "click", function() {map.zoomOut(null,true);} );

//    We add the control to to the map container and return the element 
//    for the map class to position properly.

    map.getContainer().appendChild(container);
    return container;
  }


//  The control will appear in the top left corner of the map with 7 pixels of padding.
  TextualZoomControl.prototype.getDefaultPosition = function() {
    return new GControlPosition(G_ANCHOR_TOP_LEFT, new GSize(15, 7));
  }

// Sets the proper CSS for the given button element.
  TextualZoomControl.prototype.setButtonStyle_ = function(button) {
    button.style.textDecoration = "none";
    button.style.color = "black";
    button.style.backgroundColor = "white";
//    button.style.font = "12px Verdana bold";
    button.style.fontFamily = "Verdana";
    button.style.fontSize = "12px";
    button.style.fontWeight= "bold";
    button.style.border = "1px solid gray";
    button.style.padding = "0px";
    button.style.marginBottom = "0px";
    button.style.textAlign = "center";
    button.style.width = "7em";
    button.style.height = "15px";
    button.style.cursor = "pointer";
  }