Javascript error if element is not on the page

Question

I want to have a single script file for every page, which has scripts which may or may not be required for that particular page. On my homepage I have this script:

$(function () { 

var $select = $('#select');
var $window = $(window);
var isFixed = false;
var init = $('#select').offset().top;

$window.scroll(function () {
    var currentScrollTop = $window.scrollTop();
    if (currentScrollTop > init && isFixed === false) {
        isFixed = true;
        $select.css({
            top: 0,
            position: 'fixed'
        });
        console.log("fixed");
    } else if(currentScrollTop <= init && isFixed === true) {
        isFixed = false;
        $select.css('position', 'relative');
        console.log("unfixed");
    }
});

$("#scroll").click(function () {
    $('html, body').animate({
        scrollTop: $(".jumbo").offset().top + $(".jumbo").height()
    }, 300);
});

});

However when this runs on the homepage (which doesnt have the #select element) I get this error and breaks my script:

Uncaught TypeError: Cannot read property 'top' of undefined

How can I get it to not cause errors if that script isnt required on that particual page without having to load it in its own file?

Should I have it call the function on page load?

Rory McCrossan · Accepted Answer · 2014-05-09 09:50:45Z

1

You can use the length property to check if an element exists:

var init = $select.length ? $select.offset().top : 0;

This will return 0 if the element is not present, otherwise its top offset.

answered May 9, 2014 at 9:50

Rory McCrossan

338k41 gold badges322 silver badges353 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Hannes Schneidermayer Over a year ago

.length is the way to go! :)

Collectives™ on Stack Overflow

Javascript error if element is not on the page

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related