function searchnews(){
  var keyword=$("#searchnews").val();
  if(keyword==''){
    layer.alert("关键字不能为空，请输入关键字！");
  }else{
    window.open('/channels/search.html?word='+keyword);
  }
}

document.onkeydown = function() {
  var e = window.event || arguments[0];
  //屏蔽f12
  if(e.keycode == 123) {      
    return false;
    //屏蔽ctrl+shift+i
  } else if((e.ctrlkey) && (e.shiftkey) && (e.keycode == 73)) {      
    return false;
    //屏蔽shift+f10
  } else if((e.shiftkey) && (e.keycode == 121)) {
    return false;
  }
};
//屏蔽右键单击
document.oncontextmenu = function() {
  //return false;
};
//  屏蔽ctrl+s      
document.addeventlistener('keydown', function(e) {
  if(e.keycode == 83 && (navigator.platform.match("mac") ? e.metakey : e.ctrlkey)) {
    e.preventdefault();
    return false;
  }
});