While statement crashing!

programming flash
1

I’ve nevered used a while loop before but everytime I try and implement it into my code it keeps on crashing my computer. Can anyone tell me why?

 
var tagString:String = content_txt.text;
var tags_found = true;
while (tags_found){
 var opening_tag_index:Number = tagString.indexOf("--!");
 var closing_tag_index:Number = tagString.indexOf("!--");
 trace(opening_tag_index);
 trace(closing_tag_index);
}

Thanks