In 2003, Vision Based Page Segmentation (VIPS) algorithm3 proposed to extract the semantic structure of a Web
page. Semantic structure is a hierarchical structure in which each node will correspond to a block and each node will
be assigned a value to indicate degree of coherence based on visual perception. It may not work well and in many
cases the weights of visual separators are inaccurately measured, as it does not take into account the document object
model (DOM) tree information and when the blocks are not visibly different.