JS compares the size of two numerical values ​​​​instance

Generally:

if(2 > 10)
{
alert("不正确!");
}

This comparison will not be the desired result: it is equivalent to 2 >1, take out the first digit of 10 and compare.

Solution:

if(eval(2) > eval(10))
{
alert("不正确!");
}

The eval() function is used to evaluate a code string without referencing any specific object.

<script> 
 function  check() 
 { 
 var  num1=document.form1.num1.value; 
 var  num2=document.form1.num2.value; 
 if(num2>num1)  <!-错误写法-->
 { 
 alert(&#39;num2  >  num1！&#39;); 
 return  false; 
 } 
 return  true; 
 } 
 </script>
 
 
<script> 
 function  check() 
 { 
 var  num1=document.form1.num1.value; 
 var  num2=document.form1.num2.value; 
 if(parseInt(num2)>parseInt(num1))  <!-正确写法（转换成INT）-->
 { 
 alert(&#39;num2  >  num1！&#39;); 
 return  false; 
 } 
 return  true; 
 } 
 </script>

EG:

110 and 18 are 18 in the program you wrote, because

these two numbers are both strings, and after 1 and 1 are equal, compare 1 and 8, of course 8 is big, so 18 is big

You convert it to INT type before comparison

if(parseInt(num2)>parseInt(num1))