Difference between LoadRunner HTML or URL/HTTP recording mode

It is always recommended to use HTML mode unless problems arise where URL mode is necessary. There are a few cases in whihc URL mode is necessary. For example, if your application employs certain types of refresh directives (eg. meta refresh tags) to redisplay a correct page, URL mode would be necessary.

HTML mode differs from URL mode in that HTML mode script actively parse through the returned information to obtain resources to download. URL mode does not parse, thus; resources (eg. gif, jpg, etc...) will be directly scripted into the Vuser. This will also means that script length will be increased compare to the script generated in HTML mode. Which in terns increase the memory footprints of the URL script , and may cause issues if its required to run URL mode generated script for more number of vusers on limited number of available injector boxes.

When you set the HTML mode to record resources as separate steps, it may seem identical to the URL mode, but in fact isn't. HTML mode still employs the parsing engine to detect resources. Only resources that LoadRunner can not detect will be scripted in HTML mode, whereas; 'all' resources are scripted in URL mode.

This automatic parsing mechanism will help take care of many correlation issues related to the downloading of resources, thus; I strongly recommend HTML over URL.