src/js/misc.js
function isNumber(o)  {
    return o !== undefined && o !== null &&
          (typeof o === "number" || o.constructor === Number);
}
function isNumber(o)  {
    return o !== undefined && o !== null &&
          (typeof o === "number" || o.constructor === Number);
}
function isNumber ( o ) { return o !== undefined && o !== null && ( typeof o === "number" || o . constructor === Number ) ; }
Check if the given value is number
@param {Object} v a value.
@return {Boolean} true if the given value is number
@method isNumber
@for zebkit
Check if the given value is number