Hey, check this out (from Wikipedia)! I've always just thought of them as not-likely-to-be-dangerous garden spiders. They can be found most everywhere at times including in my goldenrod: "Misumena vatia is a species of crab spider with holarctic distribution. In North America, where it the largest and most well-known flower spider, it is called the Goldenrod crab spider, because it is commonly found hunting in Goldenrod sprays in the autumn. Females can grow up to 10mm (without legs), males reach 5mm at most. Young females in the early summer may be quite small and easily overlooked. These spiders may be yellow or white, depending on the flower in which they are hunting. Especially younger females, which may hunt on a variety of flowers such as daisies and sunflowers, may change color "at will" (aggressive mimicry). Older females require large amounts of relatively large prey to produce the best possible clutch of eggs. They are, therefore, in North America most commonly found in Goldenrod (Solidago sp.), a bright yellow flower which attracts large numbers of insects, especially in autumn. It is often very hard even for a searching human to recognize one of these spiders on a yellow flower."

In the future, you might want to let us know what part of the world you are from....it helps when wanting an identification. Your critter is not a spider, though it looks like one. It's one of the many species of what are commonly called wind scorpions (though not a scorpion, either), sun spider, sun scorpion, etc. They are Arachnids, related to spiders but not spiders. These animals are active predators and can be considered helpful around your property. They can bite if handled, but they are not venomous.

We do need to know where you live to make an identification, but the spider and its webbing looks very much like a a brown widow. Red spots on the back are not uncommon at all.

It's one of the Huntsman spiders, family Sparrassidae, probably in the Heteropoda genus, though I'm not sure of the exact species, as there are nearly 100 different spiders of that genus in India alone.