模拟实现ajax加载框

function loading(p_value,str) { if (p_value) { if (!document.getElementById("load_area")) { var para1 = document.createElement("span"); var node=document.createTextNode(str); para1.appendChild(node); var para=document.createElement("div"); para.id="load_area"; var top=document.body.scrollTop+document.documentElement.scrollTop;//获取页面中的实际高度 top_position = top+157 + "px"; para.style.top =top_position; icon.style.CSSText += ";vertical-align:middle;padding-right:4px;margin-top:-2px;" para.style.cssText += ";position:absolute;left:50%;width:140px;margin-left:-70px;height:50px;line-height:50px;font-size:18px;text-overflow:ellipsis;overflow:hidden; white-space:nowrap;text-align:center;background-color: #000;border-radius:2px;-webkit-box-shadow:0 2px 2px rgba(0,0,0,0.5);color:#eee;";

var icon = new Image();icon.src="images/loading1.gif";//这里用实际路径替换document.body.appendChild(para);

para.appendChild(icon);

para.appendChild(para1); } else { document.getElementById("load_area").style.display="block"; } } else { document.getElementById("load_area").style.display="none"; } }

调用方法：loading(true,"加载中..."); loading(false)