Error: OnLoad is null or not an object

Hello All
i want to create a test plugin whose purpose is to show alert while click on editor,I have mention the plugin name in the config file.
But when ever i run the page a Java Script error message shows 'onLoad' is null or not an object
The written script is as follows

(function() {
    init: function(editor) {
        init();
        //this.editor = editor;
        var test = function() {
            alert('test from plugin');
        }

        this.document.on('onclick', test);
    }
})();

Please help
Thanks and regards
Sourav