JavaScript逻辑运算符未返回正确的值

Question

I have code like this.

No1 : <input type="text" name="no1">  value = 45
No2 : <input type="text" name="no2">  value = 55

<script>
      var no1 = $('input[name=no1]').val();
      var no2 = $('input[name=no2]').val();
</script>

But I check like this, it always returns false .

parseFloat(no1) < parseFloat(no2);
//false

Please explain theory behind this. I am new to javascript. I couldn't find it google either.

Answer 1

好吧，就目前情况而言，两个输入都具有一个空值，因此parseFloat给出NaN ，这是不可比较的，因此任何涉及它的比较都是错误的。

Answer 2

I agree with Kolink Try this.

No1 : <input type="text" name="no1">
No2 : <input type="text" name="no2">

<script>
      var no1 = document.getElementsByName('no1')[0].value;
      var no2 = document.getElementsByName('no2')[0].value;
      // will evaluate properly as long as you supply number inside input text
      parseFloat(no1) > parseFloat(no2);
</script>