add alt text to <img>s in javascript.html

javascript.html

@@ -1675,21 +1675,21 @@ $('#myCollapsible').on('hidden.bs.collapse', function () {
         </ol>
         <div class="carousel-inner">
           <div class="item active">
-            <img data-src="holder.js/900x500/auto/#777:#777" src="data:image/png;base64," alt="">
+            <img data-src="holder.js/900x500/auto/#777:#777" src="data:image/png;base64," alt="First slide image">
             <div class="carousel-caption">
               <h3>First slide label</h3>
               <p>Nulla vitae elit libero, a pharetra augue mollis interdum.</p>
             </div>
           </div>
           <div class="item">
-            <img data-src="holder.js/900x500/auto/#666:#666" src="data:image/png;base64," alt="">
+            <img data-src="holder.js/900x500/auto/#666:#666" src="data:image/png;base64," alt="Second slide image">
             <div class="carousel-caption">
               <h3>Second slide label</h3>
               <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
             </div>
           </div>
           <div class="item">
-            <img data-src="holder.js/900x500/auto/#555:#5555" src="data:image/png;base64," alt="">
+            <img data-src="holder.js/900x500/auto/#555:#5555" src="data:image/png;base64," alt="Third slide image">
             <div class="carousel-caption">
               <h3>Third slide label</h3>
               <p>Praesent commodo cursus magna, vel scelerisque nisl consectetur.</p>
@@ -1706,7 +1706,7 @@ $('#myCollapsible').on('hidden.bs.collapse', function () {
     </div><!-- /example -->
 {% highlight html %}
 <div class="item active">
-  <img src="..." alt="">
+  <img src="..." alt="...">
   <div class="carousel-caption">
     <h3>...</h3>
     <p>...</p>