JS Validate script

validator.js

'use strict';

var sr = {};
sr.Validator = function(){

    this.errors = [];

    this.messages = {
        required: 'The :input: is required',
        email: 'The :input: is not a valid email address',
        mobile: 'The :input: is not a valid mobile number',
        hex: 'The :input: is not a valid hex code',
        min: 'The min value of :input: is :num:',
        max: 'The max value of :input: is :num:'
    };

    this.initialize = function(){
        this.els = document.getElementsByClassName('validate');
    };

    this.call = function(){
        this.setRules();
        this.showErrors();
    };

    this.setError = function(el, message, num){
        el.className += ' error';
        var msg = message.replace(':input:', el.getAttribute('name'));
        return msg.replace(':num:', num);
    };

    this.setRules = function(){
        for (var i = 0; i < this.els.length; i++) {
            this.els[i].className = 'validate';
            var rules = this.els[i].getAttribute('data-validate').split('|');
            this.validate(this.els[i], rules);
        }
    };

    this.validate = function(el, rules){
        for (var i = 0; i < rules.length; i++) {
            if (rules[i].indexOf(':') !== -1) {
                var limit = rules[i].split(':');
                this[limit[0]](el, limit[1]);
            } else {
                this[rules[i]](el);
            }
        }
    };

    this.showErrors = function(){
        if(this.errors.length > 0){
            var err = document.getElementById('errors');
            err.innerHTML = null;
            for (var i = 0; i < this.errors.length; i++) {
                err.innerHTML += '<li>' + this.errors[i] + '</li>';
            }
            this.errors = [];
            event.preventDefault();
        }
    };

    /*-----------------------------------
    | Validation Rules
    ------------------------------------*/

    this.required = function(el){
        if(el.value.length === 0){
            this.errors.push(this.setError(el, this.messages.required));
        }
    };

    this.email = function(el){
        var rule = /^[\w-.+]+?@.+\.[a-z]{2,4}$/i;
        if(!rule.test(el.value)){
            this.errors.push(this.setError(el, this.messages.email));
        }
    };

    this.mobile = function(el){
        var rule = /^(\+)?[\d]{11,12}$/;
        if (!rule.test(el.value)) {
            this.errors.push(this.setError(el, this.messages.mobile));
        }
    };

    this.hex = function(el){
        var rule = /^#?(([a-fA-F0-9]){3}){1,2}$/;
        if (!rule.test(el.value)) {
            this.errors.push(this.setError(el, this.messages.hex));
        }
    };

    this.min = function(el, num){
        if(el.value < num){
            this.errors.push(this.setError(el, this.messages.min, num));
        }
    };

    this.max = function(el, num){
        if(el.value > num){
            this.errors.push(this.setError(el, this.messages.max, num));
        }
    };

    this.initialize();

};

(function(){

    window.v = new sr.Validator();
    document.getElementById('form').addEventListener('submit', function() {
        window.v.call();
    }, false);

})();

what does var sr = {}; do?

Namespaces the plugin to the sr object. If someone else has a var Validator then it won't be overwritten.