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JavaScript

Posted by Liam Maclachlan
Liam Maclachlan
22,805 Points

How do I make this jQuery function accept an 'em' measurement instead of just in int 'px' measurement?

I have this code

$('#logo').click(function() {
    if ($(window).width > 1000) {
        $('nav ul').toggle();
    }
});

but I want to use ems instead of pixels. I imagine the pseudo code would look something like this

$('#logo').click(function() {
    if ($(window).width > 33em) {
        $('nav ul').toggle();
    }
});

I feel, right now, that I will need to figure out what the browser is using as 1em and then calculate it... any ideas or more practical ways of doing this?

4 Answers

Roberto Alicata
Roberto Alicata
Courses Plus Student 39,959 Points

Try this code

$('#logo').click(function() {
    if ($(window).width() < em(33)) {
        $('nav ul').toggle();
    }
});

function em(input) {
    var emSize = parseFloat($("body").css("font-size"));
    return (emSize * input);
}

function px(input) {
    var emSize = parseFloat($("body").css("font-size"));
    return (Math.floor(input / emSize));
}

remember: when you call the width property you need to add the parenthesis to the end:

$(window).width()
Liam Maclachlan
Liam Maclachlan
22,805 Points

Ooh. I like that :) I figured out a shorter version but this is great :))

edit: changed my mind. This answer is way more robust. Great answer man. Very clean :)

Roberto Alicata
Roberto Alicata
Courses Plus Student 39,959 Points

If you need to convert em to px or vice versa more often in your code , you should create two functions to accomplish these jobs like in my code And it will be more readable when you call $(window).width() < em(33))

Kyle Daugherty
Kyle Daugherty
16,441 Points
Kyle Daugherty
Kyle Daugherty
16,441 Points

This should work:

$(window).width() / parseFloat($("html").css("font-size"));
Liam Maclachlan
Liam Maclachlan
22,805 Points

close. I think that is certainly part of what I am looking for :)

    var breakPoint = parseFloat(($('html').css('font-size')))*33;

little bit cleaner than my verion now ^_^

Liam Maclachlan
Liam Maclachlan
22,805 Points
Liam Maclachlan
Liam Maclachlan
22,805 Points

Don't worry. I had to calculate it but it works perfectly :)

$('#logo').click(function() {
    var breakPoint = parseFloat(($('html').css('font-size')))*33;

    if (newWidth > $(window).width()) {
        $('nav ul').toggle();
    }
});

Please post alternatives to this if there is a cleaner way to present/process this code ^_^

Roberto Alicata
PLUS
Roberto Alicata
Courses Plus Student 39,959 Points
Roberto Alicata
Roberto Alicata
Courses Plus Student 39,959 Points

The jQuery documentation says:

.width( value )

value

Type: String or Number

An integer representing the number of pixels, or an integer along with an optional unit of measure appended (as a string).

so if you want to use em instead of px you need to pass it in a string:

$("div").width("18em");