The processing capabilities of mobile devices are restricted by small runtime and storage memory. Because new S60 devices are constantly being developed, it is not possible to speak in definitive terms about the resources available on an S60 device. For example, the internal memory has evolved from 4 MB to even ten times more in current S60 3rd Edition devices. Still, the amount of memory available to you is limited and should be used carefully.
The following guidelines help you create widgets that comply with the limited processing capabilities of mobile devices.
Do not use complicated images and 3D graphics.
For more information, see Working with images.
Create efficient code that runs faster and consumes less CPU power.
For more information, see Using graphics and scripting effectively.
Do not use IFrames.
The in-line frame (IFrame) HTML element allows embedding an HTML document inside another HTML document. IFrames are executed as separate browser windows, which increases memory consumption and negatively affects the performance of widgets. In addition, scrolling is not supported in S60 IFrames. Therefore, using IFrames is not recommended in widgets. For more information on using IFrames, see S60 Widgets and IFrames on the Forum Nokia Wiki.