[quirksmode]

tpl = '{@categories}<h3><a href="categories/${name}">${title}</a></h3><ul>{@sub_categories}<li><a href="categories/${name}/${name1}">${title}</a></li>{/sub_categories}</ul>{/categories}';
context = {
    categories: [
        {title: '1', name: '1', sub_categories: [{title: '1.1', name1: '1'}, {title: '1.2', name1: '2'}, {title: '1.3', name1: '3'}]},
        {title: '2', name: '2', sub_categories: [{title: '2.1', name1: '1'}, {title: '2.2', name1: '2'}]},
        {title: '3', name: '3', sub_categories: [{title: '3.1', name1: '1'}]}
    ]
}

document.write( template(tpl, context) );

<h3><a href="categories/1">1</a></h3><ul><li><a href="categories/1/1">1.1</a></li><li><a href="categories/1/2">1.2</a></li><li><a href="categories/1/3">1.3</a></li></ul><h3><a href="categories/2">2</a></h3><ul><li><a href="categories/2/1">2.1</a></li><li><a href="categories/2/2">2.2</a></li></ul><h3><a href="categories/3">3</a></h3><ul><li><a href="categories/3/1">3.1</a></li></ul>