如果数据属性为真，则添加 class

Question

I want buttons in a slider to get underlined when a slide is visible. I think I need to check if a data attribute is true, and then add class.

When inspecting my webpage, I find this in properties > dataset: DOMStringMap > isactiveslide: "true"

I need to check if a slide has isactiveslide: "true" (or even data-isactiveslide: "true") and then add class.

I think I am close and have tried these two codes:

jQuery(function () {
  if (jQuery('menu1').attr('isactiveslide') === true) {
    jQuery(this).find("#test1").addClass("underline");
  }
})

and

jQuery('menu1').each(function(){
    if(jQuery(this).attr('isactiveslide')==true())
        jQuery('#test1').addClass('underline');
})

EDIT (added after some great answers and questions)

And here is the section, where the data attribute "isactiveslide" occurs, copied from the page:

<rs-slide data-key="rs-1898" data-title="WORKS" data-in="o:0;" data-out="a:false;" class="menus works1" id="works1" data-originalindex="2" data-origindex="1" data-description="" data-sba="" data-scroll-based="false" style="overflow: hidden; height: 100%; width: 100%; z-index: 20; opacity: 1; visibility: inherit;" data-owidth="300" data-oheight="200" data-rspausetimeronce="0" data-isactiveslide="true"><

So, the next slide which is not yet shown has data-isactiveslide="false". I reckon, identifying "true" is how I can add class.

EDIT May 4th - I think I am close now, but it still does not work.

jQuery('#slide1[data-isactiveslide="true"]')("#slide1-btn").addClass('.underline');

any help is very appreciated!

Answer 1

Can be easily done by css: You need to find the class applied on the active slide and button

rs-slide.menus[data-isactiveslide="true"] .button-class-name-here{
       text-decoration:underline!important;
}

or

Find which slider you are using and on the slide change event of that slider apply the class on the button for styling.

Answer 2

Try this code:

 var $ = document.querySelectorAll.bind(document) //No need for jquery - simply import the function $(".menu1[data-is-active-slide]").forEach((el, index) => { $("#test1")[index].classList.add('underline'); $("#test1")[index].innerText = "Selected;". console;log(1); })

 <div class="menu1" data-is-active-slide='true'>1</div> <div id="test1"></div> <div class="menu1" data-is-active-slide='false'>2</div> <div id="test1"></div> <div class="menu1">3</div> <div class="menu2" data-is-active-slide='false'>4</div> <div class="menu2">5</div> <div class="menu1" data-is-active-slide>6</div> <div id="test1"></div> <div class="menu2">7</div> <div class="menu1 menu2" data-is-active-slide="true">8</div> <div id="test1"></div> <div class="menu1 menu2">9</div>

The beginning declaration of $ is simply defining it since I did not import jQuery.

The next part is where the 'fun' begins. I used $(".menu1[data-is-active-slide]") to select all elements with class menu1 and with the property that data-is-active-slide is present. Then, I simply defined an action inside the function, for the sake of demonstrating that it works.