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Event triggering inside prototype

开发者 https://www.devze.com 2023-01-02 04:20 出处：网络

When I try to call \"Test\" function I get an error. How to fix that? (no jquery!) Browser:firefox error:

相关专题：javascript

When I try to call "Test" function I get an error.

How to fix that? (no jquery!)

Browser:firefox

error:

TypeError: this.Test is not a function

    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
        <title>Untitled Document</title>
        <script type="text/javascript">



            MyClass = function(){
            开发者_Python百科}

            MyClass.prototype = {

                Init: function(){
                    var txt = document.getElementById("text");

                    if (txt.addEventListener) {
                        txt.addEventListener("keyup", this.Foo, true)
                    }


                },

                Foo: function(){
                    this.Test();
                },

                Test: function(){
                    alert('OK');
                }


            }
            window.onload = function(){
                obj = new MyClass;
                obj.Init();
            }
        </script>
    </head>
    <body>
    <textarea id="text" rows="10">
    </textarea>
    </div>
</body>

It's because you reference this.Foo as the event, what actually happens is that it copies that function out of the object scope, ergo this does not exist. What most people do is use an anonymous function / wrapper around the event.