Magento 1.9.3.8中的Javascript。 如果body包含某些类并且元素id包含类，则向元素添加id

Question

The following code would assign the class "active" to the element with id="39". That would happen if two conditions are met: 1) That the body contains "hotel-stores" in its class -so the body class might be hotel-stores, hotel-stores-1, hotel-stores-2, hotel-stores-3, etc.- and 2) that the element with id="dropdown-menu" would contain the class "active".

Still, the code does not work. Do you have any ideas where the errors is, or why this code does not work? Any help would be appreciated.

if ( ($('body[class*="hotel-stores"]').length > 0)  && ( $( "#dropdown-menu" ).is( ".active" ) ))  {
   var el = document.getElementById("39");
   el.classList.add("active");
}

This second way seems to work pretty well, but only when the body class is 'hotel-stores':

if (document.body.classList.contains('hotel-stores')) {
    var el = $(document.getElementById("39"));
    el.addClassName("active");
}

Answer 1

In a comment you've said

Uncaught TypeError: Cannot read property 'length' of null at hotel-stores

That tells me that $ in that code is not jQuery, as I assumed , but some other library, probably PrototypeJS given it's a Magento site.

If you also have jQuery loaded, just change all of the $ to jQuery and it should work.

If you aren't also loading jQuery, you can do the same thing with PrototypeJS, just slightly differently because PrototypeJS isn't set-based like jQuery is:

if (document.body.className.indexOf('hotel-stores') !== -1 && $$("#dropdown-menu.active").length) {
   var el = $(document.getElementById("39"));
   el.addClassName("active");
}