// JSCodePart: var isshowflag = 1; // whether function isshowdet () {If (isshowflag = 0) {document. getelementbyid ("querydeatildiv "). style. display = ''; isshowflag = 1;} else {document. getelementbyid ("querydeatildiv "). style. display = 'none'; isshowflag = 0 ;}// body part: <Div id = "showdiv" align = "center" style = "font-size: 1px; "> <input id =" showflag "type =" button "style =" width: 100px; Height: 7px; "onclick =" isshowdet (); "> </div> <Div ID = "Querydeatildiv"> <IFRAME name = "iframe1" width = "100%" Height = "190" frameborder = "0" scrolling = "Auto"> </iframe> </Div> If the DIV contains content, if there are elements, the DIV has a minimum height by default. This is the default text height of the browser (which should be). If the DIV does not set the font-size: 10px attribute; the smallest height of the DIV is the default text height of the browser, and the opposite is based on font-size.