CSS 3 or svg wave in a background

Question

How can I build a wave on a transparent image background ?

Layout-Image:

I need th

Answer 1

I slightly improved version of akshay's answer. This includes two separate options.

OPTION 1

If aspect ratio doesn't have to be preserved, then the curve will change with width.

http://jsfiddle.net/f6n73avk/2/

OPTION 2

If the aspect ratio has to be preserved, then we have to use same units value for height and width of svg element.

http://jsfiddle.net/o1eghm7v/1/

See here I used width and height both as 100%. To change the colour you have to change the value of fill attribute.
Also, I have used absolute path commands as they are simpler to edit.

Explanation

M - command moves the drawing point to the the coordinates specified after it, or 0,5 (SVG coordinate system)

H draws Horizontal line to specified X-coordinate from the current point (0,5)

C draws cubic bezier, with first point coords as first handle, second second handle, and third is the end point.

S draws a cubic bezier, but its first handle is the reflection of the last handle of last C command about the end point of last C.

V draws vertical line to specified Y-coordinate.

Z closes the path, ie draws a straight line from current point to last M point.