How I can get the index of class(css) array

Question

How can I get the index, document.getElementsByClassName("selected")[i].css("background-color", "green"); is not working

$(function(){
    $("#but").click(function () {
        var corr = $(".lblcorrectans");
        var selected = $(".selected");

        for (var i = 0; i < model.length; i++) {
            if (corr[i].innerHTML == selected[i].innerHTML) {
                document.getElementsByClassName("selected")[i].css("background-color", "green");
            }
            else {
                document.getElementsByClassName("selected")[i].css("background-color", "red");
            }
        }
    });
});

This looks way too complicated. Can you include all the relevant code and markup? — Thomas
– Thomas, Commented Jul 21, 2020 at 11:50
@Argee sorry ..i forgot write this [model = @Html.Raw(Json.Encode(Model))] .... — Elvin
– Elvin, Commented Jul 21, 2020 at 18:22

Basheer Kharoti · Accepted Answer · 2020-07-21 12:03:09Z

1

The getElementsByClassName will return a list of Html Collection and you can access a specific element via index if it exists in the Collection.

[NOTE] However, you are using css function of the jQuery with Html Element which actually does not exist. Here's how you should do that with Jquery. You basically need to use the EQ API of the Jquery

$('.para').eq(0).css({'background-color': 'red'}) // eq(i) or whatever the index is

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<p class="para">First Para</p>
<p class="para">Second Para</p>

edited Jul 21, 2020 at 12:03

answered Jul 21, 2020 at 11:41

Basheer Kharoti

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Comments

Mark · Accepted Answer · 2020-07-21 11:59:45Z

0

Why not just iterate with forEach?

Array.from(document.getElementsByClassName('selected')).forEach(e => {
  e.style.backgroundColor = 'red';
});

edited Jul 21, 2020 at 11:59

answered Jul 21, 2020 at 11:45

Mark

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1 Comment

Thomas Over a year ago

OP is already using jQuery. Why so complicated? What is HTMLElement#css()?

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