jquery javascript verify

Question

I am having some trouble with my verification. Here, an input is being checked that it is a number, is not = to nothing, and it is greater than or = to 3 and less than or = to 12. For some reason, I am only able to successfully verify the first part. I cannot get the ">3= && <=12" to work, plz help.

}else if(question_pos==2){
        if( $("#myinput").val() != "" && Number($("#myinput").val() ) && $("#myinput").val() >= "3" && $("#myinput").val() <= "12" ){
        return true;
    }else{
        return false;
    }

This is the problem part

$("#baseline_05_ft").val() >= "3" && $("#baseline_05_ft").val() <= "12"

Answer 1

First with javascript you should be using the === operator when doing logical comparisons. Second your problem part is comparing two strings, not numbers. Try converting them to a number first.

var myInput = parseInt($('#myinput').val(), 10); //always declare a base when doing parseint
if(myInput >= 3 && myInput <= 12){
    //its valid do stuff to it
}

Answer 2

Your code is messy, that is probably what causes the error.

Write it like so:

var value = parseInt($("#myinput").val(), 10 /*radix*/);
if (isNaN(value) === false && value >= 3 && value <= 12) {
    // ..
}

Never compare strings where you mean numbers. Compare what you should be comparing. It makes the code easier to read and understand.

---

This also allows you to use strict comparison (!== and ===) as:

3 === 3; // true
3 === "3"; // false
3 == "3"; // true

I've never found a case where you want to use == instead of ===.

Answer 3

You should convert it to integers-

var myVal = parseInt($("#myinput").val(), 10);
if(!isNaN(myVal) && myVal >= 3 && myVal <= 12) {
    //do stuff
}

Answer 4

You are comparing strings, not numbers. There is no value that compares lexically greater than "3…" but lower than "1…".

if (question_pos==2) {
    var strVal = $("#myinput").val();
    var val = Number(strVal);
    return strVal != "" && !isNaN(val) && val >= 3 && val <= 12;
}