for example if we have something like this:
http://chart.apis.google.com/chart?chxl=1:|0|10|100|1,000|10,000|100,000|1,000,000|2:||++++++++++++++++++++++++++++++++++++++++++Excretion+in+Nanograms+per+gram+creatinine+milliliter+(logarithmic+scale)|&chxp=1,0|2,0&chxr=0,0,129.8|1,0,3&chxs=0,676767,13.5,0,lt,676767|1,676767,13.5,0,l,676767&chxtc=0,-1000&chxt=y,x,x&chbh=a,1,0&chs=640×465&cht=bvs&chco=A2C180&chds=0,129.8&chd=t:0,0,0,0,1,1,9,24,33,49,64,91,101,112,113,102,116,118,102,94,70,67,44,35,29,28,21,8,8,5,0,5,1,2,3,0,0,1,2,7,4,0,1,3,1,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0&chdl=n=1477&chtt=S.%20Blake%20Kelly,%20MD%20-%20Buprenorphine%20Graph
why not replace all the + with a space? does the browser read the URL differently?
The URI format, which is used by the HTTP protocol, does not allow spaces in URLs.
See RFC 2396 section 2.4.3