JavaScript —如何制定规则以确保用户输入的值介于两个特定数字之间

Question

How can I make sure a user entered a value between two numbers on a form? In this instance, one of the boxes asks the user to enter their GPA. I need to ensure that the number is between 0 and 4. They cannot click the submit button until the number is between 0 and 4.

Can I do something like:

GPA: {
min: 0,
max: 4
}

If you look at the code below I already have one rule (Student ID input box is required)... How can I incorporate the GPA rule in there?

$(document).ready(function(){
$('#studentID').focus();
//validate form
$('#tuition').validate({
rules: {
    studentID: {
        required: true,
    }
},//end rules

messages: {
    studentID: {
        required: "Please enter your student ID.",
    }
},//end messages    

});//end validate

//School auto-complete

Answer 1

You'd use the range option

$('#tuition').validate({
    rules: {
        studentID: {
            required: true,
        },
        GPA: {
            range : [0, 4]
        }
    },
    messages: {
        studentID: {
            required: "Please enter your student ID."
        },
        GPA: {
            range: "Please enter a number between 0 and 4."
        }
    }
});

Answer 2

您实际上并不需要Javascript，只需在input代码中使用min和max属性，如下所示：

<input type="number" min="0" max="4" />