function sr(){

string=document.forms[0].elements[0].value
n=string.length
si=Math.round(Math.random()*n)
ri=Math.round(Math.random()*n)
search=string.charAt(ri)
replace=string.charAt(si)
document.forms[0].elements[0].value=string.replace(search,replace)
timeID=setTimeout("sr()",80)

}