Opera JavaScript Flaw--with Statement Problems

This document demonstrates an apparent flaw in the Opera Web browser. For some objects, particularly form elements, the with statement does not appear to work properly.

Code

JavaScript functions like the following are attached to the buttons on the form below.

    function btnSetFieldsA_OnClick ()
    {
        with (document.frmTest) {
            txtBox1.value = "Method A";
        }
    }

    function btnSetFieldsB_OnClick ()
    {
        with (document.frmTest.txtBox1) {
            value = "Method B";
        }
    }

    function btnResetField_OnClick ()
    {
        with (document.frmTest) {
            txtBox1.value = "-----";
        }
    }

Demonstration and Results

Load this document in the Opera Web browser and click the Method A and Method B buttons. The code attached to the Method A button will work properly, causing the text Method A to appear in the text box. The code attached to the Method B button, however, will not work properly in the Opera browser, and the text in the text box will not change. This behavior was also observed when the with statement was used directly in the <INPUT> tags for the buttons.

Discovered By

This behavior was discovered by Charles L. Taylor, who also prepared this example.