ie8下解析textare里的内容时空格和换行会丢失问题

/**
 * 将换行和空格元素替换
 * @param str
 * @returns
 */
function replaceTextarea1(str){
var reg=new RegExp("\r\n","g"); 
var reg1=new RegExp(" ","g"); 


str = str.replace(reg,"<br>"); 
str = str.replace(reg1,"&nbsp"); 


return str; 
}