否则，如果在JavaScript

Question

我正在尝试根据用户输入来计算字符串并显示一些消息：

$('#myInput').keyup(function() {
    if(this.value.length<=158)
     $('#charCount').text('We will deduct 1 credit from your account');
    else if(this.value.length>158 || this.value.length<316)
         $('#charCount').text('We will deduct 2 credit from your account');
    else if(this.value.length>316 || this.value.length<400)
        $('#charCount').text('We will deduct 3 credit from your account');
});

http://jsfiddle.net/p9jVB/11/

问题是最后一个else if不起作用...我错过了什么吗？

Answer 1

看起来您的意思是&&，而不是||

$('#myInput').keyup(function() {
    if(this.value.length<=158)
         $('#charCount').text('We will deduct 1 credit from your account');
    else if(this.value.length>158 && this.value.length<=316)
         $('#charCount').text('We will deduct 2 credit from your account');
    else if(this.value.length>316 && this.value.length<400)
        $('#charCount').text('We will deduct 3 credit from your account');
});

Answer 2

 else if(this.value.length>158 || this.value.length<316) $('#charCount').text('We will deduct 2 credit from your account'); else if(this.value.length>316 || this.value.length<400) $('#charCount').text('We will deduct 3 credit from your account'); 

世界上每个数字都大于158 或小于316，因此永远不会达到替代条件。