The JavaScript click event and hidden input elements

I was recently working with the HTML canvas element and wanted to attach an event to the canvas that would fire the click event of a file input element. I would then hide the input element so that the canvas element was the only way to browse for files.

My first attempt was simple enough.

document.getElementById('canvas').onclick = function(e) {
    document.getElementById('filepicker').click();
};

Now it’s time to hide the filepicker input element. Setting the elements style to display: none worked fine with Firefox but Chrome does not allow click events to be fired from hidden HTML elements. The solution is to use a bit of CSS to effectively hide the element. I came across this method over at quirksmode where they use it to style input boxes with CSS. I adapted it to my needs and came up with this solution.

With CSS we set the opacity to 0 rendering the element invisible. The different declarations are for cross-browser compatibility.

.fakehidden {
    -moz-opacity: 0;
    filter:alpha(opacity: 0);
    opacity: 0;
}

Setting the input elements class tofakehidden effectively hides the element from the user yet click events can be fired as usual.

See also

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