function check_project_name(){
    if($('project_name').value == ''){
        $('error_div').innerHTML = 'You must enter a project name<br>';
    }else{
        var url = 'check_url.php';
        var project_name = $('project_name').value;
        new Ajax.Request(
                url,
                {
                    method: 'get',
                    parameters: {
                        project_name:project_name
                    },
                    onSuccess: function(transport){
                        var res = eval(transport.responseText);
                        if(res[0]==0){
                            $('error_div').innerHTML = res[1];
                        }else{
                            $('error_div').innerHTML = '';
                            window.open(res[1], 'win');
                        }
                    }
                }

        )
    }
}