Validate if an input only contains numeric values - Javascript

Question

I am currently using the script below to take my inputs and convert them to what I want with some validation included. I have got my server side validation set up and would like to have some client side also, I have validated the lengths of the inputs but now need to ensure that they only contain numbers. This is for the Variables day, month and year. I have tried using IsNumeric() but to no avail

<script type="text/javascript">
function timeMachine() {

    var day     = $("#date_day").val();
    var month = $("#date_month").val();
    var year    = $("#date_year").val();

    if (day == "" && month == "" && year != ""){
        if (year.length != 4){
            alert("Please enter a valid year!");
        } else{
            window.location = "/date/" + year ;
        }   
    } else if (day == "" || month == "" || year == ""){
        alert("Please enter a full date!");
    } else{
        var myDate = new Date(year, month-1, day);

        var monthNames = [ "january", "february", "march", "april", "may", "june","july", "august", "september", "october", "november", "december" ];   

        window.location = "/date/" + year + "/" + monthNames[myDate.getMonth()] + "/" + day;
    }
    return false;
}
</script>

Thoughts?

score 4 · Accepted Answer · answered Dec 11 '15 at 11:06

4

Simple way, if you are supporting modern browsers, use:

<input type="number" />

If you can use JavaScript (and jQuery), you can set up an event:

$(input).keydown(function (e) {
  if (e.keyCode >= 48 && e.keyCode <= 57) { //0-9 only
    return;
  }
  return false;
});

Else, at the final level, you may use:

/^\d+$/.test(input.value);

answered Dec 11 '15 at 11:06

Praveen Kumar Purushothaman

164,888
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I understand what you are saying, but adding input type="number" means that my php to limit the length is no longer working – L. Smith Dec 11 '15 at 11:12
1

@L.Smith How can PHP control what your client side is, can you kindly clarify? – Praveen Kumar Purushothaman Dec 11 '15 at 11:13

score 1 · Answer 2 · answered Dec 11 '15 at 11:09

1

Try the below function:

function isNumber( num ) {
    return ! isNaN( parseFloat( num ) ) && isFinite( num );
}

answered Dec 11 '15 at 11:09

web-nomad

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Validate if an input only contains numeric values - Javascript

2 Answers2