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jQuery .css() method not applying styles conditionally based on viewport size

πŸ‘€ Views: 1022 πŸ’¬ Answers: 1 πŸ“… Created: 2025-08-20
jquery css responsive JavaScript

I'm having trouble with I'm sure I'm missing something obvious here, but I'm relatively new to this, so bear with me. I'm trying to conditionally apply a CSS style using jQuery based on the viewport width, but it's not working as expected. I want to change the background color of a div to red if the viewport width is less than 600 pixels, and to blue otherwise. However, when I resize the browser window, the background color doesn't update correctly after the initial load. Here's the code I've implemented: ```javascript $(document).ready(function() { function updateBackgroundColor() { if ($(window).width() < 600) { $('#myDiv').css('background-color', 'red'); } else { $('#myDiv').css('background-color', 'blue'); } } updateBackgroundColor(); // Initial call $(window).resize(function() { updateBackgroundColor(); }); }); ``` Initially, the background color changes correctly on page load. However, when I resize the window, sometimes it doesn’t change back to blue when I expand it past 600 pixels. I checked the console for errors, but there are no behavior messages. I am using jQuery version 3.6.0. Is there a best practice or a more reliable way to handle this viewport resizing in jQuery? What might I be missing here? Am I missing something obvious? I'm coming from a different tech stack and learning Javascript. Thanks in advance! For reference, this is a production application. My team is using Javascript for this application. I'd love to hear your thoughts on this.