function initRollOverImages() {
	
  var image_cache = new Object();
  
  $(".swap").each(function(i) {
    var imgsrc = this.src;
    var dot = this.src.lastIndexOf('.');
    var imgsrc_on = this.src.substr(0, dot) + '_on' + this.src.substr(dot, 4);
    image_cache[this.src] = new Image();
    image_cache[this.src].src = imgsrc_on;
    
	$(this).hover(
      function() { this.src = imgsrc_on;
	  
		/* IE5.5、IE6かどうか判定 */
		var badBrowser = (/MSIE ((5\.5)|6)/.test(navigator.userAgent) && navigator.platform == "Win32");
		if (badBrowser){ fixPng(this); }
		
	  
	  },
      function() { this.src = imgsrc;
	  
		/* IE5.5、IE6かどうか判定 */
		var badBrowser = (/MSIE ((5\.5)|6)/.test(navigator.userAgent) && navigator.platform == "Win32");
		if (badBrowser){ fixPng(this); }
		
	  
			
	  }
	);
  });
  
}

$(document).ready(initRollOverImages);