对于多行，请使用"main_section"之类的类代替id.然后单击添加主要"按钮时，使用 $(this).parent().prev() ".

For multiple row use class like 'main_section' instead of id. and when click on 'Add Main' button append the clone to the immediately preceding sibling 'main_section' using $(this).parent().prev()'.

将是主要部分的jQuery代码.

jQuery code for main section will be.

    jQuery(function($){
        var unique_id = 0;
        var appendto = '';
        jQuery(document).on('click', 'button.click', function(){
        var appendto = $(this).parent().prev();
            $(this).parent().prev().find(".row1:first").clone().find("input,select").each(function() {
  -----
    }).end().appendTo(appendto);

完整代码.

Complete code.

 jQuery(function($){
var unique_id = 0;
jQuery('.sectionClick').on('click', function(){
    $(".section .row2:first").clone().find("h4,div,input,select").each(function() {
        this.name = $(this).attr("name")+"_"+unique_id; //make name unique of new row
        this.id = $(this).attr("id")+"_"+unique_id; // make id unique of new row
        this.value = '';  //make value empty of new row
        var fieldName = $(this).attr('name');
        $(this).siblings().attr('for', fieldName);
    }).end().appendTo(".section").find('.row1').not(':first').remove(); //append only first row, remove other 
    unique_id++;
});
});

jQuery(function($){
var unique_id = 0;
var appendto = '';
jQuery(document).on('click', 'button.click', function(){
    var appendto = $(this).parent().prev();
    $(this).parent().prev().find(".row1:first").clone().find("input,select").each(function() {

        this.name = $(this).attr("name")+"_"+unique_id; //make name unique of new row
        this.id = $(this).attr("id")+"_"+unique_id; // make id unique of new row
        this.value = '';  //make value empty of new row
        var fieldName = $(this).attr('name');
        $(this).siblings().attr('for', fieldName);
    }).end().appendTo(appendto);
    unique_id++;

});
});

 

   <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.0/jquery.min.js"></script>
 <div class="container-fluid section">
	<div class="row2">
		<h4>
		Section Details
		</h4>
		<div id="main" class="main_section">
			<div class="row1">
				<div class="control-group">
					<label for="caption">caption</label>
					<input name="caption" id="caption" type="text">
				</div>
			</div>
		</div>
		<div class="btn-group" role="group" aria-label="Basic example">
			<button type="button" class="btn btn-space main click">Add Main</button>
		</div>
	</div>
</div>
<div class="btn-group" role="group" aria-label="Basic example">
	<button type="button" class="btn btn-space sectionClick">Add Another Section</button>
</div>