Comparison of JavaScript string values

Comparison of JavaScript string values

1. Problem background

Today, I encountered a problem in the project: two input boxes, one with a value of 8.4 and the other with a value of 21.3. When comparing the values in the two input boxes, a value greater than 8.4 is displayed.

 

2. Problem Analysis

First, obtain the value in the input box as a string, while the string comparison is based on the ASCII code. Because the ASCII Code of 8 is larger than the ASCII code of 2, 8.4 is greater than 21.3.

 

3. Problem Verification

(1) design source code

 

<Script type = text/javascript> function compareData () {var data1 = document. getElementById (inval ). value; var data2 = document. getElementById (typev ). value; if (data1> data2) {alert (data1 + greater than + data2);} else {alert (data1 + less than or equal to + data2); }}</script>
(2) running result

 

 

4. Solution

(1) convert a string to a numeric value

 

Function compareData () {var data1 = document. getElementById (inval ). value; var data2 = document. getElementById (typev ). value; if (Number (data1)> Number (data2) {alert (data1 + greater than + data2);} else {alert (data1 + less than or equal to + data2 );}}

(2) running result