Auto running jQuery method & Calling jQuery method from onClick attribute in HTML

Issue

I'm struggling with jQuery. Please help me...

When loading a page, the jQuery function is automatically executed, and at the same time, I'd like to implement this function in button click.

[Previously]

After loading the page, the jQuery function is automatically executed immediately.

And, there is no response when clicking the button.

html

<button type="button" class="btn btn-primary btn-sm" id="btn_add">LookUp</button>

jQuery

<script type="text/javascript">
        
        $(function() { 

            ..skip..

        });

</script>

[Current situation]

After loading the page, the jQuery function is not automatically executed.

But It works well when clicking the button.

html

<button type="button" class="btn btn-primary btn-sm" id="btn_add" onclick="$(this).Lookup();">Lookup</button>

jQuery

<script type="text/javascript">

        $.fn.Lookup = function() {

            ..skip..

        };

</script>

[Goal]

Keep the jQuery function running automatically after loading the page.

Implement so that the jQuery function works even when clicking the LookUp button.

How should I fix this?

Solution

What you should do is create a function for Lookup and then call this function during document ready and button click. Refer the code snippet. I would be happy to explain further if you don't understand the code.

Edit: Also $.fn.<xyz> should ideally be used for extending/creating generic functionality and not for specific/page specific ones.

$(function(){
    //This will bind Lookup function to the button click event
    $("#btn_add").on("click", Lookup);
    //This will immediately call the Lookup function on document ready event (startup)
    Lookup();
});

function Lookup() {
  //do something
  alert("Looking up");
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<button type="button" class="btn btn-primary btn-sm" id="btn_add">LookUp</button>

Answered By - Sang Suantak