I need to add a class to a div on 12 different pages. Bellow is the code I've tried to use that don't work.

<script>
window.onload = init;
var divsWithClass = null;


function init() {
    if (window.location.href.indexOf("page1") >= -1 &&
       window.location.href.indexOf("page2") >= -1 &&
         window.location.href.indexOf("page3/") >= -1 &&
        window.location.href.indexOf("page4") >= -1 &&
       ) {
        this.divsWithClass = document.getElementsByClassName("sub-menu");
        var index = 0;
        while (index < divsWithClass.length) {
            divsWithClass[index].className += "et_pb_slide_dropdown_opened";
            index++;
        }
    }
    console.log(divsWithClass);
}
</script>