How can I limit possible inputs in a HTML5 “number

Question

For <input type="number"> element, maxlength is not working. How can I restrict the maxlength for that number element?

Answer 1

it's very simple, with some javascript you can simulate a maxlength, check it out:

//maxlength="2"
<input type="number" onKeyDown="if(this.value.length==2) return false;" />

Answer 2

If you are looking for a Mobile Web solution in which you wish your user to see a number pad rather than a full text keyboard. Use type="tel". It will work with maxlength which saves you from creating extra javascript.

Max and Min will still allow the user to Type in numbers in excess of max and min, which is not optimal.

Answer 3

And you can add a max attribute that will specify the highest possible number that you may insert

<input type="number" max="999" />

if you add both a max and a min value you can specify the range of allowed values:

<input type="number" min="1" max="999" />

The above will still not stop a user from manually entering a value outside of the specified range. Instead he will be displayed a popup telling him to enter a value within this range upon submitting the form as shown in this screenshot:

Answer 4

You can combine all of these like this:

<input name="myinput_drs"
oninput="maxLengthCheck(this)"
type = "number"
maxlength = "3"
min = "1"
max = "999" />

<script>
  // This is an old version, for a more recent version look at
  // https://jsfiddle.net/DRSDavidSoft/zb4ft1qq/2/
  function maxLengthCheck(object)
  {
    if (object.value.length > object.maxLength)
      object.value = object.value.slice(0, object.maxLength)
  }
</script>

Update:
You might also want to prevent any non-numeric characters to be entered, because object.length would be an empty string for the number inputs, and therefore its length would be 0. Thus the maxLengthCheck function won't work.

Solution:
See this or this for examples.

Demo - See the full version of the code here:
http://jsfiddle.net/DRSDavidSoft/zb4ft1qq/1/

Update 2: Here's the update code: https://jsfiddle.net/DRSDavidSoft/zb4ft1qq/2/

Update 3: Please note that allowing more than a decimal point to be entered can mess up with the numeral value.

Answer 5

I know there's an answer already, but if you want your input to behave exactly like the maxlength attribute or as close as you can, use the following code:

(function($) {
 methods = {
    /*
     * addMax will take the applied element and add a javascript behavior
     * that will set the max length
     */
    addMax: function() {
        // set variables
        var
            maxlAttr = $(this).attr("maxlength"),
            maxAttR = $(this).attr("max"),
            x = 0,
            max = "";

        // If the element has maxlength apply the code.
        if (typeof maxlAttr !== typeof undefined && maxlAttr !== false) {

            // create a max equivelant
            if (typeof maxlAttr !== typeof undefined && maxlAttr !== false){
                while (x < maxlAttr) {
                    max += "9";
                    x++;
                }
              maxAttR = max;
            }

            // Permissible Keys that can be used while the input has reached maxlength
            var keys = [
                8, // backspace
                9, // tab
                13, // enter
                46, // delete
                37, 39, 38, 40 // arrow keys<^>v
            ]

            // Apply changes to element
            $(this)
                .attr("max", maxAttR) //add existing max or new max
                .keydown(function(event) {
                    // restrict key press on length reached unless key being used is in keys array or there is highlighted text
                    if ($(this).val().length == maxlAttr && $.inArray(event.which, keys) == -1 && methods.isTextSelected() == false) return false;
                });;
        }
    },
    /*
     * isTextSelected returns true if there is a selection on the page. 
     * This is so that if the user selects text and then presses a number
     * it will behave as normal by replacing the selection with the value
     * of the key pressed.
     */
    isTextSelected: function() {
       // set text variable
        text = "";
        if (window.getSelection) {
            text = window.getSelection().toString();
        } else if (document.selection && document.selection.type != "Control") {
            text = document.selection.createRange().text;
        }
        return (text.length > 0);
    }
};

$.maxlengthNumber = function(){
     // Get all number inputs that have maxlength
     methods.addMax.call($("input[type=number]"));
 }

})($)

// Apply it:
$.maxlengthNumber();

Answer 6

Maycow Moura's answer was a good start. However, his solution means that when you enter the second digit all editing of the field stops. So you cannot change values or delete any characters.

The following code stops at 2, but allows editing to continue;

//MaxLength 2
onKeyDown="if(this.value.length==2) this.value = this.value.slice(0, - 1);"