JavaScript 开关比较不起作用

Question

jQuery:

var Page = parseInt($(".active_pagination").data("number"));
  	var First = parseInt($(".pagination_number:first").data("number"));
  	var Last = parseInt($(".pagination_number:last").data("number"));
  	alert("Page: "+Page+" First: "+First+" Last: "+Last);
  	switch(Page){
  		case (Page === First):
  		    alert("First");
  		    $(".prev").closest('li').hide();
  		    $(".next").closest('li').show();
  		break;
  		case (Page === Last):
  		    alert("Last");
  		    $(".prev").closest('li').show();
  		    $(".next").closest('li').hide();
  		break;
  		default:
  		    alert("Default");
  		    $(".prev").closest('li').show();
  		    $(".next").closest('li').show();
  	}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<li><a href="#" class="pagination_list pagination_number active_pagination" data-number="1">1</a></li>
<li><a href="#" class="pagination_list pagination_number" data-number="2">2</a></li>
<li><a href="#" class="pagination_list pagination_number" data-number="3">3</a></li>
<li><a href="#" class="pagination_list pagination_number" data-number="4">4</a></li>
<li><a href="#" class="pagination_list pagination_number" data-number="5">5</a></li>

我把所有变量都解析为Int，然后执行比较，但还是不行。我不知道它是如何不断执行默认条件的。

Answer 1

在 switch case block 中，您实际上需要根据 switch 参数中使用的变量值设置条件语句。

var Page = parseInt($(".active_pagination").data("number"));
  	var First = parseInt($(".pagination_number:first").data("number"));
  	var Last = parseInt($(".pagination_number:last").data("number"));
  	alert("Page: "+Page+" First: "+First+" Last: "+Last);
  	switch(Page){
  		case (First):
  		    alert("First");
  		    $(".prev").closest('li').hide();
  		    $(".next").closest('li').show();
  		break;
  		case (Last):
  		    alert("Last");
  		    $(".prev").closest('li').show();
  		    $(".next").closest('li').hide();
  		break;
  		default:
  		    alert("Default");
  		    $(".prev").closest('li').show();
  		    $(".next").closest('li').show();
  	}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<li><a href="#" class="pagination_list pagination_number active_pagination" data-number="1">1</a></li>
<li><a href="#" class="pagination_list pagination_number" data-number="2">2</a></li>
<li><a href="#" class="pagination_list pagination_number" data-number="3">3</a></li>
<li><a href="#" class="pagination_list pagination_number" data-number="4">4</a></li>
<li><a href="#" class="pagination_list pagination_number" data-number="5">5</a></li>