对于layui框架源码兼容性微调介绍

// 修改部分定位写法

var showDown = function(){

  // 将样式复位

  dl.css({

    top: '',

    left: '',

    right: ''

  })

  var top = reElem.offset().top + reElem.outerHeight() + 5 - $win.scrollTop()

  ,dlHeight = dl.outerHeight(), dlWidth = dl.outerWidth(), winWidth = $(window).width();

  index = select[0].selectedIndex; //获取最新的 selectedIndex

   // 判断是否在最右边的临界点

  if (dlWidth + reElem.offset().left > winWidth) {

    dl.css({

      left: 'auto',

      right: 0

    })

  }

  reElem.addClass(CLASS+'ed');

  dds.removeClass(HIDE);

  nearElem = null;

  //初始选中样式

  dds.eq(index).addClass(THIS).siblings().removeClass(THIS);

  //上下定位识别

  if(top + dlHeight > $win.height() && top >= dlHeight){

    reElem.addClass(CLASS + 'up');

  } else {

    // 定位重写定义

    // 动画需要的距离和弹窗的间隔，这是根据 layui 的样式来的，理论应该计算

    var ANIM_UP = 30, SPACE = 5;

    var reElemBottom = reElem.get(0).getBoundingClientRect().bottom;

    var dlTop = parseInt(dl.css('top'));

    var winHeight = $win.height();

    if (reElemBottom + dlHeight + ANIM_UP > winHeight ) {

      var computeValue = dlTop - (reElemBottom + SPACE - (winHeight - dlHeight - ANIM_UP))

      dl.css('top', computeValue)

    }

  }

  followScroll();

}

// 第一处修改

Tree.prototype.tree = function() {

   // 大概在 line 48

   var li = $(['<li '+ (hasChild ? " is-branch " : " is-leaf ") + (item.spread ? 'data-spread="'+ item.spread +'"' : '') +'>'

}

// 第二处修改

// 大概在 72 - 76 注释掉

/*+ ('<i class="layui-icon layui-tree-'+ (hasChild ? "branch" : "leaf") +'">'+ (

         hasChild ? ( item.spread ? icon.branch[1] : icon.branch[0]) : icon.leaf) +'</i>') */ //节点图标