sale 优化

 {{#data}}
 {{#data}}
-{{#if ../discountActivity}}
-    {{> common/floor-header-more}}
-{{/if}}
-<ul class="discount-list">
-    {{#list}}
-    <li>
-        <a href="/product/sale/discount/detail?id={{id}}&channel={{@root.channel}}">
-            <img class="lazy" data-original="{{image2 cover_url w=640 h=250 q=60}}" />
-            <p class="discount-cont">
-                <span class="discount-title">{{title}}</span>
-                <span class="discount-time {{#if warn_color}}red-color{{/if}}">{{time}}</span>
-            </p>
-        </a>
-    </li>
-    {{/list}}
-</ul>
+    {{#if ../discountActivity}}
+        {{> common/floor-header-more}}
+    {{/if}}
+    <ul class="discount-list">
+        {{#list}}
+            <li>
+                <a href="/product/sale/discount/detail?id={{id}}&channel={{@root.channel}}">
+                    {{#within @index 3}}
+                        <img src="{{image2 cover_url w=640 h=250 q=60}}"/>
+                    {{^}}
+                        <img class="lazy" data-original="{{image2 cover_url w=640 h=250 q=60}}"/>
+                    {{/within}}
+                    <p class="discount-cont">
+                        <span class="discount-title">{{title}}</span>
+                        <span class="discount-time {{#if warn_color}}red-color{{/if}}">{{time}}</span>
+                    </p>
+                </a>
+            </li>
+        {{/list}}
+    </ul>
 {{/data}}
 {{/data}}

@@ -60,5 +60,19 @@ module.exports = {
         } else {
         } else {
             return opt.inverse(this);
             return opt.inverse(this);
         }
         }
+    },
+
+    /**
+     * 小于某zhi
+     *
+     * @param variable
+     * @param number
+     */
+    within: function(variable, number, opt) {
+        if (variable < number) {
+            return opt.fn(this);
+        } else {
+            return opt.inverse(this);
+        }
     }
     }
 };
 };