js正表达式替换文本

function ReplaceFace(chatbody)
{  
    if(Josn_face.length>0)
    {
        for (var i = 0; i < Josn_face.length; i++) {
            var faceName = eval("/\[" + Josn_face[i].FaceTitle + "]/ig");
            var replaceHtml = "<img title='" + Josn_face[i].FaceTitle + "' style='cursor:pointer' src='" + Josn_face[i].FaceUrl + "'>"
            chatbody = chatbody.replace(faceName, replaceHtml);
        }
        return chatbody;
    }
    else
    {
        return chatbody;
    }
   
    
}