发布于 2017-06-23 06:03:49 | 89 次阅读 | 评论: 0 | 来源: 网友投递

这里有新鲜出炉的Javascript教程,程序狗速度看过来!

JavaScript客户端脚本语言

Javascript 是一种由Netscape的LiveScript发展而来的原型化继承的基于对象的动态类型的区分大小写的客户端脚本语言,主要目的是为了解决服务器端语言,比如Perl,遗留的速度问题,为客户提供更流畅的浏览效果。


瀑布流主要应用在图片展示页面上。如果有一大批图片需要展示,原始图片尺寸不一致,又希望每张图片都能不剪裁,完整显示,那么就要给图片规定一个宽度,解放它们的高度。利用网页高度不限这个特性,充分利用页面的空间,尽可能的展示多的图片。下面我们就来详细探讨下

  布局不是基于float,也不是基于绝对定位,看最下面的html,css就知道了。也没有满篇烦人的html插入,代码很清爽


function getIndex(index) {
  if (index < 10) {
    index = "00" + index;
  } else if (index < 100) {
    index = "0" + index;
  }
  return index;
}
var $ = function(id) {
  return document.getElementById(id);
};
require([ "avalon-min" ], function(avalon) {
  var waterfall = {
      load_items : null,
      loaded_items:[],
      col_num : 0,// 列数
      waterfall_model : null,
      col_width : 200,
      loaded_num : 0,
      init_num : 0,
      loading : false,
      start:0,
      resizing:false,
      find_shortest_col : function() {
      // 找出最小高度的列
        var a = avalon($('row0')).height(), min_i = 0;
        for ( var i = 1; i < this.col_num; i++) {
          var b = avalon($('row' + i)).height();
          if (b < a) {
            min_i = i;
            a = b;
          }
        }
        return min_i;
      },
      init : function(data) {
        this.load_items = data;
        this.loaded_items=this.loaded_items.concat(data);
        this.waterfall_model = waterfall_model;
        this.col_num = Math.floor(avalon(window).width()
            / this.col_width);
        this.init_num = this.col_num;
        for ( var j = 0; j < this.col_num; j++) {
          waterfall_model.img_list.push([]);
        }
        for ( var j = 0; j < this.col_num; j++) {
         // 第一行图片
          var a={};
          a.src=getIndex(data[j].src);
          a.height=data[j].height;
          a.text=data[j].text;
          waterfall_model.img_list[j].push(a);
        }
        this.start=this.col_num;
      },
      add_item : function(i) {
        var a = this.find_shortest_col();
        var b={};
        var c=this.load_items[this.init_num+i];
        if(c){
          b.src=getIndex(c.src);
          b.height=c.height;
          b.text=c.text;
          waterfall_model.img_list[a].push(b);
        }
      },
      resize_item:function(i){
        //console.log(i);
        var a = this.find_shortest_col();
        var b={};
        var c=this.loaded_items[this.init_num+i];
        if(c){
          b.src=getIndex(c.src);
          b.height=c.height;
          b.text=c.text;
          waterfall_model.img_list[a].push(b);
        }
      }
    };
    var waterfall_model = avalon.define("waterfall",function(vm) {// vm
              vm.img_list = [];
              vm.rendered = function() {// 每次图片加载渲染后执行
                 
                if(waterfall.resizing){
                  if (waterfall.loaded_num+ waterfall.init_num<waterfall.loaded_items.length){
                    waterfall.loaded_num++;
                    waterfall.resize_item(waterfall.loaded_num);
                    //waterfall.start++;
                  }
                }else{
                   
                  if (waterfall.loaded_num + waterfall.init_num <waterfall.load_items.length){
                    waterfall.loaded_num++;
                    waterfall.add_item(waterfall.loaded_num);
                    waterfall.start++;
                  }
                }
              };
    });
  avalon.config({
    debug:false
  });
  avalon.scan();
  function debouncer( func , timeout ) {
      var timeoutID , timeout = timeout || 200;
      return function () {
       var scope = this , args = arguments;
       clearTimeout( timeoutID );
       timeoutID = setTimeout( function () {
         func.apply( scope , Array.prototype.slice.call( args ) );
       } , timeout );
      }
    }
  avalon.post("http://localhost/css/test.php?start=0", function(data) {
  // 加载第一次
    waterfall.init(data);
  }, "json");
  window.onscroll =debouncer( function ( e ) {
    var scrollTop = avalon(window).scrollTop(), windowHeight = avalon(
    window).height(), documentHeight = avalon(document).height();
    if (windowHeight + scrollTop==documentHeight) {
        avalon.post("http://localhost/css/test.php?start="+(waterfall.start), function(data) {
        // 加载第一次
        waterfall.resizing=false;
        waterfall.load_items=data;
        waterfall.loaded_items=waterfall.loaded_items.concat(data);
        waterfall.loaded_num =waterfall.init_num=0;
        waterfall.add_item(0);
        }, "json");
    }
  });
  window.onresize = debouncer( function ( e ) {
    var windowWidth = avalon(window).width(), k = Math
    .floor(windowWidth / 200), detect_left = avalon(
    $('waterFallDetect')).offset().left;
    if (Math.abs(detect_left) >= 199) {
      waterfall.col_num = Math.floor(avalon(window).width()
      / waterfall.col_width);
      waterfall_model.img_list = [];
      for ( var j = 0; j < waterfall.col_num; j++) {
        waterfall_model.img_list.push([]);
      }
      waterfall.resizing=true;
      waterfall.loaded_num =waterfall.init_num=0;
      //waterfall.start=0;
      waterfall.resize_item(0);
    }
  },30) ;
});

html


<div id='wrap' ms-controller="waterfall">
  <ul ms-each-els="img_list" id='wrap_row'>
    <li ms-each-el="els" ms-attr-id='row{{$index}}'
      data-each-rendered='rendered'>
      <p>
        <img
          ms-src="http://cued.xunlei.com/demos/publ/img/P_{{el.src}}.jpg"
          width='192' ms-attr-height='{{el.height}}'> <span>{{el.src}}</span>
      </p>
    </li>
    <li id='waterFallDetect' ms-if='$last'></li>
  </ul>
</div>

css


#wrap ul li {
display: inline-block;
*display: inline;
zoom: 1;
vertical-align: top;
font-size: 16px;
}
#wrap ul li p {
margin: 5px 2.5px;
border: 1px solid red;
min-width: 192px;
min-height: 100px;
}
#wrap span {
display: block;
}
#waterFallDetect {
width: 192px;
height: 100px;
border: 1px solid red;
}

以上所述就是本文的全部内容了,希望大家能够喜欢。



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