看如下的javascript脚本: if (window.XMLHttpRequest) { //Mozilla, Safari,...IE7 alert('Mozilla, Safari,...IE7 '); if(!window.ActiveXObject){ // Mozilla, Safari,... alert('Mozilla, Safari'); } else { alert('IE7'); } } else { alert('IE6'); }  

  看如下的javascript脚本:
if (window.XMLHttpRequest) { //Mozilla, Safari,...IE7
alert('Mozilla, Safari,...IE7 ');
if(!window.ActiveXObject){ // Mozilla, Safari,...
alert('Mozilla, Safari');
} else {
alert('IE7');
}
} else {
alert('IE6');
}
  看看运行效果:
<script language="javascript">
if (window.XMLHttpRequest) { //Mozilla, Safari,...IE7
alert('Mozilla, Safari,...IE7 ');
if(!window.ActiveXObject){ // Mozilla, Safari,...
alert('Mozilla, Safari');
} else {
alert('IE7');
}
} else {
alert('IE6');
}
</script>