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BackButton Module

The BackButton Module is used to set the parameters of the Back Button. When clicked, the Back button will navigate to the previously loaded page, if any.

Syntax

backButton (Module) <META> Syntax

<META HTTP-Equiv="BackButton" content="[parameter]">

BackButton JavaScript Object Syntax:
By default the JavaScript Object 'backButton' will exist on the current page and can be used to interact directly with the backButton.
To Set backButton parameters via JavaScript use the following syntax: backbutton.parameter = 'value'; remembering to enclose your value in quotes where appropriate.

e.g. backButton.left = 'value';
To set multiple EMML parameters / events on a single line use the following syntax: backbutton.setEMML("[Your EMML Tags]");

e.g. backButton.setEMML("left:value");
BackButton Ruby Object Syntax:
By default the Ruby Object 'BackButton' will exist on the current page and can be used to interact directly with the BackButton. All Methods, Parameters and Events are the same as JavaScript, however, notice 'BackButton' needs to start with an uppercase letter. Another difference in Ruby is that methods do not end in '()'
To Set BackButton parameters via Ruby use the following syntax: BackButton.parameter = 'value' remembering to enclose your value in quotes where appropriate.

e.g. BackButton.left = 'value'

Parameters

Items listed in this section indicate parameters, or attributes which can be set.

Name Possible Values Description Default Value
left:[Value] Positive number, representing pixels Sets the X position of the Back Button. To the right of the address bar
top:[Value] Positive number, representing pixels Sets the Y position of the BackButton. To the right of the address bar
height:[Value] Positive number, representing pixels Sets the height of the Back Button. Dependant on screen resolution
width:[Value] Positive number, representing pixels Sets the width of the Back Button. Dependant on screen resolution
imageUp:[Value] URL Sets the image to be displayed when the Back Button is in the up state. See Remarks. Default image
imageDown:[Value] URL Sets the image to be displayed when the Back Button is in the down state. See Remarks. Default image
visibility:[Value] visible, hidden Sets the visibility of the back button. Hidden.

Remarks

Use of Images on Buttons.

Images can be specified as local to the device or on an HTTP / FTP server, just specify the required protocol as part of your URL (file://\, HTTP:// and FTP://). Image will be scaled to the size of the button. JPEG and GIF images are only supported on WM devices. Both CE and WM support BMP files.

Default Positions

By default this control will be placed a the top of the screen. On Windows Mobile if the ‘FullScreen’ configuration setting is disabled the control will need to be moved, otherwise it will appear beneath the task bar.

Switching to Other Applications

All controls are designed to be shown on top of RhoElements. If you require to switch to an application other than RhoElements you should minimize RhoElements to ensure the buttons do not remain shown. (Not applicable to Enterprise Tablet)

Screen Orientation

When the screen orientation changes, either using the ScreenOrientation tag or by rotating a device with hardware support, the command areas will automatically move and resize to fit the new layout. However the buttons themselves are not moved and in some cases this may result in them being off the screen or not in the expected position. If so they must be moved manually by detecting the ScreenOrientationEvent.

Use in Production

This API is designed for debugging your application only and should not be used in production

Requirements

RhoElements Version 1.0.0 or above
Supported Devices All supported touch devices.
Minimum Requirements None.
Persistence Persistent - Changes to this module will persist when navigating to a new page.

HTML/JavaScript Examples

The following example shows the Back button, sets its left and top coordinates to 50, and its width and height to 30 pixels.

<META HTTP-Equiv="BackButton" Content="Visibility:Visible">
<META HTTP-Equiv="BackButton" Content="Left:50">
<META HTTP-Equiv="BackButton" Content="Top:50">
<META HTTP-Equiv="BackButton" Content="Width:30">
<META HTTP-Equiv="BackButton" Content="Height:30">

The following example shows the Back button, sets its width to 30 pixels, its left coordinate to 50, and displays the back_up.gif / back_down.gif image on it (resizing the images if necessary).

<META HTTP-Equiv="BackButton" Content="Width:30; Left:50; ImageUp:url('http://myaddress/back_up.gif'); ImageDown:url('http://myaddress/back_down.gif'); Visibility:Visible"> 
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