function convert_tag(){

	var str;
	 for (j=0; j<document.forms[0].length; j++) {
	
		 if (document.forms[0].elements[j].type=="text" || document.forms[0].elements[j].type=="textarea"){													   
			str = document.forms[0].elements[j].value;
						
			while (str.indexOf("<")!=-1) {
				str = str.replace("<","&lt;");
			}

			while (str.indexOf(">")!=-1) {
				str = str.replace(">","&gt;");
			}

			str = str.replace(/\&lt\;B\&gt\;/g,"<B>");
			str = str.replace(/\&lt\;\/B\&gt\;/g,"</B>");
			
			str = str.replace(/\&lt\;I\&gt\;/g,"<I>");
			str = str.replace(/\&lt\;\/I\&gt\;/g,"</I>");

			str = str.replace(/\&lt\;U\&gt\;/g,"<U>");
			str = str.replace(/\&lt\;\/U\&gt\;/g,"</U>");
			
			//var regexp = //g;
			
			var t = str.match(/img\ssrc=\"\/\gaiji\/[a-z0-9][a-z0-9][a-z0-9][a-z0-9]\.png\"/g);
			
			if (t!=null){
				if (t.length>0) {
					for (k=0;k<t.length;k++){
						str = str.replace("&lt;" +  t[k] + "&gt;","<" + t[k] + ">");
					}
			    }
			}
			document.forms[0].elements[j].value=str;
		}
	}
	return;
}