function replaceAll(str,reg1,reg2){
var len1 = reg1.length;
var len2 = reg2.length;
var index = 0 ;
index = str.indexOf(reg1);
while(index>0){
str = str.substring(0,index)+reg2+str.substring(index+len1);
index = str.indexOf(reg1,index+len2);
}
return str;
}