NumberField.js

/**
 * @class Ext.form.NumberField
 * @extends Ext.form.TextField
 * Numeric text field that provides automatic keystroke filtering and numeric validation.
 * @constructor
 * Creates a new NumberField
 * @param {Object} config Configuration options
 */
Ext.form.NumberField = function(config){
    Ext.form.NumberField.superclass.constructor.call(this, config);
};

Ext.extend(Ext.form.NumberField, Ext.form.TextField,  {
    /**
     * @cfg {String} fieldClass The default CSS class for the field (defaults to "x-form-field x-form-num-field")
     */
    fieldClass: "x-form-field x-form-num-field",
    /**
     * @cfg {Boolean} allowDecimals False to disallow decimal values (defaults to true)
     */
    allowDecimals : true,
    /**
     * @cfg {String} decimalSeparator Character(s) to allow as the decimal separator (defaults to '.')
     */
    decimalSeparator : ".",
    /**
     * @cfg {Number} decimalPrecision The maximum precision to display after the decimal separator (defaults to 2)
     */
    decimalPrecision : 2,
    /**
     * @cfg {Boolean} allowNegative False to require only positive numbers (defaults to true)
     */
    allowNegative : true,
    /**
     * @cfg {Number} minValue The minimum allowed value (defaults to Number.NEGATIVE_INFINITY)
     */
    minValue : Number.NEGATIVE_INFINITY,
    /**
     * @cfg {Number} maxValue The maximum allowed value (defaults to Number.MAX_VALUE)
     */
    maxValue : Number.MAX_VALUE,
    /**
     * @cfg {String} minText Error text to display if the minimum value validation fails (defaults to "The minimum value for this field is {minValue}")
     */
    minText : "The minimum value for this field is {0}",
    /**
     * @cfg {String} maxText Error text to display if the maximum value validation fails (defaults to "The maximum value for this field is {maxValue}")
     */
    maxText : "The maximum value for this field is {0}",
    /**
     * @cfg {String} nanText Error text to display if the value is not a valid number.  For example, this can happen
     * if a valid character like '.' or '-' is left in the field with no number (defaults to "{value} is not a valid number")
     */
    nanText : "{0} is not a valid number",

    // private
    initEvents : function(){
        Ext.form.NumberField.superclass.initEvents.call(this);
        var allowed = "0123456789";
        if(this.allowDecimals){
            allowed += this.decimalSeparator;
        }
        if(this.allowNegative){
            allowed += "-";
        }
        var keyPress = function(e){
            var k = e.getKey();
            if(!Ext.isIE && (e.isNavKeyPress() || k == e.BACKSPACE || (k == e.DELETE && e.button == -1))){
                return;
            }
            var c = e.getCharCode();
            if(allowed.indexOf(String.fromCharCode(c)) === -1){
                e.stopEvent();
            }
        };
        this.el.on("keypress", keyPress, this);
    },

    // private
    validateValue : function(value){
        if(!Ext.form.NumberField.superclass.validateValue.call(this, value)){
            return false;
        }
        if(value.length < 1){ // if it's blank and textfield didn't flag it then it's valid
             return true;
        }
        value = String(value).replace(this.decimalSeparator, ".");
        if(isNaN(value)){
            this.markInvalid(String.format(this.nanText, value));
            return false;
        }
        var num = this.parseValue(value);
        if(num < this.minValue){
            this.markInvalid(String.format(this.minText, this.minValue));
            return false;
        }
        if(num > this.maxValue){
            this.markInvalid(String.format(this.maxText, this.maxValue));
            return false;
        }
        return true;
    },

    // private
    parseValue : function(value){
        return parseFloat(String(value).replace(this.decimalSeparator, "."));
    },

    // private
    fixPrecision : function(value){
       if(!this.allowDecimals || this.decimalPrecision == -1 || isNaN(value) || value == 0 || !value){
           return value;
       }
       // this should work but doesn't due to precision error in JS
       // var scale = Math.pow(10, this.decimalPrecision);
       // var fixed = this.decimalPrecisionFcn(value * scale);
       // return fixed / scale;
       //
       // so here's our workaround:
       var scale = Math.pow(10, this.decimalPrecision+1);
       var fixed = this.decimalPrecisionFcn(value * scale);
       fixed = this.decimalPrecisionFcn(fixed/10);
       return fixed / (scale/10);
    },

    // private
    decimalPrecisionFcn : function(v){
        return Math.floor(v);
    }
});