js实现简单锁屏功能实例

//********* 锁屏DIV ***************************
function LockScreen(tag,title,width,height,url)
{
  if (tag) //锁屏
  {
    var lockdiv = document.getElementById("lockscreen");
    if (lockdiv!=null)
    {
      lockdiv.style.display = "block";
      var subdiv = document.getElementById("subdialog");
      if (subdiv!=null)
      {
        subdiv.style.display = "block";
        document.getElementById("dialog1").src = url;
      }      
    }else{
      //创建新的锁屏DIV,并执行锁屏
      var tabframe= document.createElement("div");
      tabframe.id = "lockscreen";
      tabframe.name = "lockscreen";
      tabframe.style.top = '0px';
      tabframe.style.left = '0px';
      tabframe.style.height = '100%';
      tabframe.style.width = '100%';
      tabframe.style.position = "absolute";
      tabframe.style.filter = "Alpha(opacity=10)";
      tabframe.style.backgroundColor="#000000";
      tabframe.style.zIndex = "99998";
      document.body.appendChild(tabframe);
      tabframe.style.display = "block";
      //子DIV
      var subdiv = document.createElement("div");
      subdiv.id = "subdialog";
      subdiv.name = "subdialog";
      subdiv.style.top = Math.round((tabframe.clientHeight-height)/2);
      subdiv.style.left = Math.round((tabframe.clientWidth-width)/2);
      subdiv.style.height = height+'px';
      subdiv.style.width = width+'px';
      subdiv.style.position = "absolute";
      subdiv.style.backgroundColor="#000000"; 
      subdiv.style.zIndex = "99999";
      subdiv.style.filter = "Alpha(opacity=100)";
      subdiv.style.border = "1px";
      //subdiv.onmousemove = mouseMoveDialog;
      //subdiv.onmousedown = control_onmousedown;
      //subdiv.onmouseup = mouseUp;
      document.body.appendChild(subdiv);
      subdiv.style.display = "block";
      //subdiv.onclick=UNLockScreen;
      var iframe_height = height-30;
      var titlewidth = width;
      var html = "<table border='0' cellpadding='0' cellspacing='0'>"
      html += "<tr><td></td><td>";
      html += "<table><tr><td><font color='#FFFFFF'><b>"+title+"</b></font></td><td style='width:30px' valign='top'><img src='/images/images/close.gif' ></img></td></tr></table>";
      html += "</td><td></td></tr>";
      html += "<tr><td></td><td style='height:100px;'><iframe id='dialog1' frameborder=0 style='width:"+titlewidth+"px;height:" + iframe_height + "px' src='"+url+"'></iframe></td><td></td></tr>";
      html += "<td></td><td></td><td></td>";
      html += "</table>";
      subdiv.innerHTML = html;
    }
  }else{
    //解屏
    var lockdiv = document.getElementById("lockscreen");
    if (lockdiv!=null)
    {
      lockdiv.style.display = "none";
    }
    var subdiv = document.getElementById("subdialog");
    if (subdiv!=null)
    {
      subdiv.style.display = "none";
    }
  }
}
function UNLockScreen(){
  LockScreen(false);
}

//阻止F5或者鼠标右键刷新,使锁屏失效。
document.onkeydown = function(){
 if(event.keyCode==116) {
 event.keyCode=0;
 event.returnValue = false;
 }
}
document.oncontextmenu = function() {event.returnValue = false;}