$.fn.validate = function(input){
    var errclass = "input-error";
    var focused;
    var form = $(this);

    // Clear errors
    function clear() {
        $(this).parent().removeClass(errclass);
        $(this).parent().find('div.input-error').remove();
    }
    if (!input) {
        $(this).find('.error ul').empty();
        $(this).find('input').each(clear);
        $(this).find('textarea').each(clear);
        $(this).find('select').each(clear);
    } else $(input).each(clear);
    
    if (!input) $('div.input-error').remove();

    function validate(name,p,s){
        var inputs;
        if (input)
            inputs = $(input).parent().find(name);
        else
            inputs = $(this).find(name);
        // Here is where errors are inserted
        inputs.each(function(){
                // Don't bother validating an already invalid input
                if ($(this).parent().hasClass(errclass)) return true;
                if (p.call(this)) {
                    $(this).parent().addClass(errclass);
                    // Focus the input
                    if (!focused && !input) {
                        $(this).focus();
                        focused = true;
                    }
                    //if (input) {
                    var msg = $('<div class="input-error"></div>');
                    msg.text(s);
                    if ($(this).next().text()=='')
                        $(this).parent().append(msg);
                    else
                        msg.insertBefore($(this).next());
                }
            });
    }

    validate.call(this,
                  'input.required',
                  function(){ return (this.type == 'text' || this.type == 'password') && this.value.replace(/[ ]+/,'') == ''; },
                  "must be completed");

    validate.call(this,
                  'textarea.required',
                  function(){ return this.value.replace(/[ ]+/,'') == ''; },
                  "must be completed");

    validate.call(this,
                  'select.required',
                  function(){ return this.value.replace(/[ ]+/,'') == ''; },
                  "must be completed");

    validate.call(this,
                  'input.postcode',
                  function(){
                      if (this.value=='') return false;
                      else return !this.value.toUpperCase().match(/^[A-Z0-9 ]+$/); 
                  },
                  "must be a valid UK post code");

    validate.call(this,
                  'input.email',
                  function(){
                      if (this.value=='') return false;
                      else return !this.value.match(/^[^@]+@[^@\.]+\.[^@\.]+/); 
                  },
                  "must be a valid email");

    validate.call(this,
                  'input.alphanum',
                  function(){
                      if (this.value=='') return false;
                      else return !this.value.match(/^[a-zA-Z0-9]+$/); 
                  },
                  "must be letters or numbers");

    validate.call(this,
                  'input.integer',
                  function(){
                      if (this.value=='') return false;
                      else return !this.value.match(/^[-]{0,1}[0-9]+$/); 
                  },
                  "must be a valid integer number. E.g. 23, 1, 0, 36214, etc.");

    validate.call(this,
                  'input.overzero',
                  function(){
                      if (this.value=='') return false;
                      else if (!this.value.match(/^[-]{0,1}[0-9]+$/)) return false;
                      else return this.value < 1;
                  },
                  "must be over zero");

    validate.call(this,
                  'input.telnumber',
                  function(){
                      if (this.value=='') return false;
                      else return !this.value.toUpperCase().match(/^[0-9 -+]{6,25}$/); 
                  },
                  "must be a valid telephone number. Examples: 01234 123 456, 01234123123, +44 01421-234-234");

    validate.call(this,
                  'input.password',
                  function(){
                      if (this.value=='') return false;
                      else return !this.value.toUpperCase().match(/[^0-9]*[0-9][^0-9]*[0-9][^0-9]*/); 
                  },
                  "should be at least six characters in length, and "+
                  "include at least three numbers");

    var anyErrors = false;
    $(this).find('.input-error').each(function(){
        anyErrors = true;
        return false;
    });
    return !anyErrors;
}

    $(document).ready(function(){
            $('form').each(function(){
                    var form = $(this);
                    function val() {
                        $(this).change(function(){ 
                                form.validate(this);
                            });
                    }
                    form.find('input').each(val);
                    form.find('textarea').each(val);
                    form.find('select').each(val);

                    form.submit(function(){
                            $(this).find('div.error').remove();
                            return $(this).validate();
                        });
                });
        });

jQuery.fn.extend({
        scrollTo : function(speed, done) {
            return this.each(function() {
                    var targetOffset = $(this).offset().top;
                    $('html,body').animate({scrollTop: targetOffset}, speed,"linear", done);
                });
        }
    });