Javascript – jQuery load more data on scroll

ajaxjavascriptjqueryscroll

I am just wondering how can i implement more data on scroll only if the div.loading is visible.

Usually we look for page height and scroll height, to see if we need to load more data. but the following example is little complicated then that.

Following image is perfect example. there are two .loading div's on the drop down box. When user scroll the content, whichever is visible it should start loading more data for it.

enter image description here

So how can i find out if .loading div is visible to user yet or not? So i can start loading data for that div only.

Best Answer

In jQuery, check whether you have hit the bottom of page using scroll function. Once you hit that, make an ajax call (you can show a loading image here till ajax response) and get the next set of data, append it to the div. This function gets executed as you scroll down the page again.

$(window).scroll(function() {
    if($(window).scrollTop() == $(document).height() - $(window).height()) {
           // ajax call get data from server and append to the div
    }
});

Related Solutions

Javascript – n “exists” function for jQuery

In JavaScript, everything is 'truthy' or 'falsy', and for numbers 0 means false, everything else true. So you could write:

if ($(selector).length)

You don't need that >0 part.

Javascript – Add table row in jQuery

The approach you suggest is not guaranteed to give you the result you're looking for - what if you had a tbody for example:

<table id="myTable">
  <tbody>
    <tr>...</tr>
    <tr>...</tr>
  </tbody>
</table>

You would end up with the following:

<table id="myTable">
  <tbody>
    <tr>...</tr>
    <tr>...</tr>
  </tbody>
  <tr>...</tr>
</table>

I would therefore recommend this approach instead:

$('#myTable tr:last').after('<tr>...</tr><tr>...</tr>');

You can include anything within the after() method as long as it's valid HTML, including multiple rows as per the example above.

Update: Revisiting this answer following recent activity with this question. eyelidlessness makes a good comment that there will always be a tbody in the DOM; this is true, but only if there is at least one row. If you have no rows, there will be no tbody unless you have specified one yourself.

DaRKoN_ suggests appending to the tbody rather than adding content after the last tr. This gets around the issue of having no rows, but still isn't bulletproof as you could theoretically have multiple tbody elements and the row would get added to each of them.

Weighing everything up, I'm not sure there is a single one-line solution that accounts for every single possible scenario. You will need to make sure the jQuery code tallies with your markup.

I think the safest solution is probably to ensure your table always includes at least one tbody in your markup, even if it has no rows. On this basis, you can use the following which will work however many rows you have (and also account for multiple tbody elements):

$('#myTable > tbody:last-child').append('<tr>...</tr><tr>...</tr>');

Best Answer

Related Solutions

Javascript – n “exists” function for jQuery

Javascript – Add table row in jQuery

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