My script below checks that a form input contains at least 10 digits, besides other text. Everything works fine, except that it also counts spaces as a digit. Can anyone help with this bug?

Jsfiddle: /

function(){
    var text = input.value;
    var totalNrOfDigits = 0;
    for(var i = 0; i < text.length; i++){
        if(!isNaN(text[i])){
            totalNrOfDigits++;
        }
    }
    if(totalNrOfDigits < 10){
        alert("Invalid input");
    }
}

My script below checks that a form input contains at least 10 digits, besides other text. Everything works fine, except that it also counts spaces as a digit. Can anyone help with this bug?

Jsfiddle: http://jsfiddle/BG4du/

function(){
    var text = input.value;
    var totalNrOfDigits = 0;
    for(var i = 0; i < text.length; i++){
        if(!isNaN(text[i])){
            totalNrOfDigits++;
        }
    }
    if(totalNrOfDigits < 10){
        alert("Invalid input");
    }
}

• javascript

• have you tried: if(!isNaN(text[i]) && text[i]!=" " ){ – durbnpoisn Commented Apr 7, 2014 at 15:13
• So you need those spaces after all or not? – Roko C. Buljan Commented Apr 7, 2014 at 15:15
• No spaces needed. Amit Joki's solution works great!! thank you all! – Malasorte Commented Apr 7, 2014 at 15:23

5 Answers 5

Do this:

function(){
    var text = input.value.replace(/\s/g,"");
    var totalNrOfDigits = 0;
    for(var i = 0; i < text.length; i++){
        if(!isNaN(text.charAt(i))){
            totalNrOfDigits++;
        }
    }
    if(totalNrOfDigits < 10){
        alert("Invalid input");
    }
}

replace(" ","") just replaces the first occurence. My solution removes all whitespace.

According to MDN, isNaN is broken

Since the very earliest versions of the isNaN function specification, its behavior for non-numeric arguments has been confusing. When the argument to the isNaN function is not of type Number, the value is first coerced to a Number. The resulting value is then tested to determine whether it is NaN. Thus for non-numbers that when coerced to numeric type result in a valid non-NaN numeric value (notably the empty string and boolean primitives, which when coerced give numeric values zero or one), the "false" returned value may be unexpected; the empty string, for example, is surely "not a number." …

I'd remend something like this instead:

var code = text.charCodeAt(index);
if(code >= 48 && code <= 57){
    totalNrOfDigits++;
}

48 is the character code for '0' and 57 is the character code for '9'.

Use this:

function() {
    var text = input.value.replace(/\s+/g,""); //removes spaces
    var totalNrOfDigits = 0;
    for(var i = 0; i < text.length; i++){
        if(!isNaN(text[i])){
            totalNrOfDigits++;
        }
    }
    if(totalNrOfDigits < 10){
        alert("Invalid input");
    }
}

An alternative to the answers above:

function(){
    var text = input.value;
    var totalNrOfDigits = 0;
    for(var i = 0; i < text.length; i++){
        if(/\d/.test(text[i])){
            totalNrOfDigits++;
        }
    }
    if(totalNrOfDigits < 10){
        alert("Invalid input");
    }
}

Here's an updated JSFiddle

You could just use

var totalNrOfDigits = input.value.match(/\d/g).length;
if(totalNrOfDigits < 10)
    alert("Invalid input");

Demo