Update browser.js
Update browser.js

changed url[0] to url.charAt(0), because IE7 not support to get the first char of a string like this:  string[0];
andradedev/director,tanzhihang/director,tanzhihang/director,webx32/director,GerHobbelt/director,cpg1111/director,lzhengms/director,pocketjoso/director,lzhengms/director,meleslilijing/director,pandoraui/director,stonegithubs/director,webx32/director,andradedev/director,stonegithubs/director,sheldonzf/director,GerHobbelt/director,mylikes/director,sheldonzf/director,ks3dev/director,meleslilijing/director,kiritoe/director,ks3dev/director,flatiron/director,kiritoe/director,fadeit/director,vitalsource/director,pandoraui/director,vitalsource/director,fadeit/director,cpg1111/director,pocketjoso/director,mylikes/director