In the HTML, I had add  onclick="return validate()" in the button HTML.

<input type="submit" id="form_save" value="Save" onclick="return form_validate()">

Then, I had prepare the form_validate() function in a separate js file, it would work properly.

2. function form_validation(){
3. console.log('abc');
4. return false;
5. }
6. 
   

But, when I try to use the jquery function as usual by bounding (function ($) {})(jQuery), it show an error " Uncaught ReferenceError: form_validation is not defined ". 

How can I use the jquery function in form_validation() ?

1. (function ($) {
3.           function form_validation(){
4. console.log('abc');
5. return false;
6.           }
7. 
   
8.           $('selector').click(...................) // other jquery function work properly.
9. 
   
10. })(jQuery)