$(document).ready(PageInit);

function PageInit() {
  MenuInit();
  var now = new Date();
  var date = now.getFullYear()+'-'+(now.getMonth()+1)+'-'+now.getDate();
  if(date=='2010-4-21'){
    img_gray();
  }
}

function MenuInit() {
  var menu2 = $(".menu2 ul");
  window.global = window.global || {};
  window.global.menu2 = window.global.menu2 || (menu2.length+1);

  //找到menu1下的所有li/a
  $(".menu li").each(function (i) {
    //对找到的对象添加显示和隐藏子菜单的方法
    $(this).mouseover(function(){ ShowMenu2(menu2,i);});
  });

  $(".menu2").hover(function(){},function(){ShowMenu2(menu2, window.global.menu2);});
  ShowMenu2(menu2, window.global.menu2);
}

//显示某个子菜单
function ShowMenu2(menu2, index) {
  $(".menu li a").each(function (i) {
    if(i == index) $(this).css('background-color','#f60');
    else $(this).css('background-color','#666');
  });

  menu2.each(function(i){
    if (i == index) {
      $(menu2[i]).show();
    }else{
      $(menu2[i]).hide();
    }
  });
}


function img_gray() {
  //ie
  $('head').append('<style type="text/css">body { filter: Gray;}</style>');
  //firefox, chrome
  $('img').each(function(){
    try {
      var obj_img = $(this).after('<canvas></canvas>');
      var obj_canvas = $(this).next();
      var canvas = obj_canvas.get(0);
      canvas.width = this.width;
      canvas.height = this.height;
      var ctx = canvas.getContext('2d');
      ctx.drawImage(this, 0, 0);
      var canvasData = ctx.getImageData(0, 0, canvas.width, canvas.height);
      for (var x = 0; x < canvasData.width; x++) {
          for (var y = 0; y < canvasData.height; y++) {
              // Index of the pixel in the array
              var idx = (x + y * canvas.width) * 4;

              // The RGB values
              var r = canvasData.data[idx + 0];
              var g = canvasData.data[idx + 1];
              var b = canvasData.data[idx + 2];

              // Update the values of the pixel;
              var gray = (r + g + b) / 3;
              canvasData.data[idx + 0] = gray;
              canvasData.data[idx + 1] = gray;
              canvasData.data[idx + 2] = gray;
          }
      }
      ctx.putImageData(canvasData, 0, 0);
      obj_img.remove();
    } catch(e){}
  })

  /**
   *

  var canvas = document.getElementById('myCanvasElt');
  var ctx = canvas.getContext('2d');

  var source = document.querySelector("img");
  canvas.width = source.width;
  canvas.height = source.height;

  var canvasData = ctx.getImageData(0, 0, source.width, source.height);
  for (var x = 0; x < canvasData.width; x++) {
      for (var y = 0; y < canvasData.height; y++) {

          // Index of the pixel in the array
          var idx = (x + y * canvas.width) * 4;

          // The RGB values
          var r = canvasData.data[idx + 0];
          var g = canvasData.data[idx + 1];
          var b = canvasData.data[idx + 2];

          // Update the values of the pixel;
          var gray = (r + g + b) / 3;
          canvasData.data[idx + 0] = gray;
          canvasData.data[idx + 1] = gray;
          canvasData.data[idx + 2] = gray;
      }
  }
  ctx.putImageData(canvasData, 0, 0);
   */

}