URL이 올바른지 체크

function isValidURL(turl){ 
 var ReturnValue=true;
 var inValidReg="[\n\t]";
 var inValidRegOne="^[\n\t\=\\\+\!\@\#\$\%\^\&\*\(\)\{\}\[\\]]$";
 var inValidRegBegin="^(\#|JAVASCRIPT:|MAILTO:)";
 var inValidRegEnd="\.(GIF|JPG|BMP|SWF|PDF|ZIP|RAR|ALZ|GZ|DOC|PPT|XLS|HWP|CSS|LOG|TXT|TGZ|ICO)$";

 turl=turl.toUpperCase().trim();

 //url valid check
 if(turl=="")ReturnValue=false;
 if(isMatch(inValidReg,turl))ReturnValue=false;
 if(isMatch(inValidRegOne,turl))ReturnValue=false;
 if(isMatch(inValidRegBegin,turl))ReturnValue=false;
 if(isMatch(inValidRegEnd,turl))ReturnValue=false;

 return ReturnValue;
}