Handling load file dialog with selenium webdriver

Question

I'm trying to handle 'select files to load' dialog with the help of selenium webdriver. Here is HTML:

<form class="upload">
    <button class="btn" data-capture="" type="button">Browse</button>
    <input class="hide" type="file" accept="..." multiple="" data-file-input=""/>
</form>

What i'm trying to do:

1. remove class='hide';
2. senndkeys with file path, after elemnt is unhidden;
3. hide element back.

Here is the code to do this:

JavascriptExecutor js = (JavascriptExecutor) webDriver;
js.executeScript("$('.hide:not(.layout)').removeClass('hide')");
(webDriver.findElement(By.cssSelector(".upload>input"))).sendKeys("path_to_file");
js.executeScript("$('.hide:not(.layout)').addClass('hide')");

But i got exception on 3rd line:

"Runtime.evaluate threw exception: TypeError: Cannot read property 'click' of null"

What am i doing wrong?

Answer 1

Thank you, user1433852. It looks like the problem was really with wait. After adding waiting for ajax, it starts to work!