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JavaScript jQuery Basics Working with jQuery Collections Stopping the Browser's Default Behavior

Vladimir Plokhotniuk
Vladimir Plokhotniuk
5,464 Points
Posted by Vladimir Plokhotniuk
Vladimir Plokhotniuk
5,464 Points

Why i copie the code from video 1:1, ind code dont working property.

$pdfs.on('click', function(event) { if ($(':checked').lenght === 0) { event.preventDefault(); alert('Allow dw!'); } });

but this working, not full: $pdfs.on('click', function(event) { event.preventDefault();
}

3 Answers

josephr
josephr
18,877 Points
josephr
josephr
18,877 Points

You misspelled length in that first bit of code (($(':checked').lenght === 0)). To be honest, I'm not sure that is the only problem, but it certainly would prevent the code form working.

Daniel Amazigo
PLUS
Daniel Amazigo
Courses Plus Student 11,357 Points
Daniel Amazigo
Daniel Amazigo
Courses Plus Student 11,357 Points

Hi! To add to what Joseph explained, I believe JavaScript runs in the order it was written i.e. top to bottom (with some exceptions - like when functions are called) and that's the way the code is loaded onto your browser, I think.

So, the way Joseph has written his code ensures there's actually a checkbox to do a " (':checked').length " for - otherwise the section where the check runs will 'wonder' where the checkbox is, because it hasn't 'seen' the checkbox prior to that moment.

Vladimir Plokhotniuk
Vladimir Plokhotniuk
5,464 Points
Vladimir Plokhotniuk
Vladimir Plokhotniuk
5,464 Points

i deleted " .length " and write again, and that working! But i checked, there wasn't missed spaces or another mistakes, i dont know why that dont worked. Thanks Joseph for help

Joseph Thomas
Joseph Thomas
Courses Plus Student 9,067 Points
Joseph Thomas
Joseph Thomas
Courses Plus Student 9,067 Points

I am not sure if anyone answered your question yet, but I will do it now. I also ran into the same problem. My solution was to append the button before the if statement. I have pasted my code below.

const $odd = $('a:odd');
const $secureLinks = $('a[href^="https://"]');
const $pdfs = $('a[href$="pdf"]');
const $pdfCheckbox = $('<label><input type="checkbox"> Allow PDF Downloads </label>');

$secureLinks.attr('target', '_blank');
$pdfs.attr('download', true);
$('#links').append($pdfCheckbox); //Append button here
$secureLinks.addClass('secure');
$pdfs.addClass('pdf');

$pdfs.on('click', function(e){
    if($(':checked').length === 0) {
      event.preventDefault();
      alert('Please check the box to allow PDF downloads.');
    }     
});