JavaScript Error Correction: $(document).on('click', '.qmulimg', function() ... )

There are a few errors in your code. Here are the corrected lines:

1. Line 10: Change 'item_id' to 'data_id' in var item_id = $(this).attr('data_id');

2. Line 12: Change imgid.toString(); to imgid.join(",");

Here is the corrected code:

$(document).on('click', '.qmulimg', function() {

	var inputp = $(this);
	$(this).remove();		
	var imgid = [];
	
	inputp.closest('.qq_uploader').find('.qq_u_img').find('.qq_muti_img').each(function() {

		var data_id =  $(this).attr('data_id');
		imgid.push(data_id); 
	});
	var imgidlist = imgid.join(",");			
		
	inputp.closest('.qq_uploader').find('.q_uid_img').val(imgidlist);		  

});

Please note that this code assumes that you have the necessary HTML elements with the appropriate classes defined in your document.