JavaScript
Well the answer is simple. you have to stick to methods that are not malicious and that are not in any way cheating the search engine algorithm. The the tricks must not dupe the visitor into viewing or arriving at some non relevant content other than those promoted for. What is white hat today could have been black hat a year ago. Its the Black Hat seos who like hackers let us find loop holes in SE algorithms and hence let us further improve our technology. Certain Black hat concepts that were not particularly damaging to the search engine reputation or adversely affect the promotions of competitors business are gradually taken as white hat.
Some of the simple guidelines would be to refraining form: -
1. malicious link building to bring down your competitors site to boost your serp.
2. using hidden text with font color matching the background.
3. Using alt text that are far form what your image is about or your page content is about.
4. Using JavaScript to alter page content after page load.
