<!-- todayDate = new Date(); date = todayDate.getDate(); month= todayDate.getMonth() +1; year= todayDate.getYear(); document.write("今天是") document.write("<br>") if(navigator.appName == "Netscape") { document.write(1900+year); document.write("年"); document.write(month); document.write("月"); document.write(date); document.write("日"); document.write("<br>") } if(navigator.appVersion.indexOf("MSIE") != -1) { document.write(year); document.write("年"); document.write(month); document.write("月"); document.write(date); document.write("日"); document.write("<br>") } if (todayDate.getDay() == 5) document.write("星期五") if (todayDate.getDay() == 6) document.write("星期六") if (todayDate.getDay() == 0) document.write("星期日") if (todayDate.getDay() == 1) document.write("星期一") if (todayDate.getDay() == 2) document.write("星期二") if (todayDate.getDay() == 3) document.write("星期三") if (todayDate.getDay() == 4) document.write("星期四")

//-->

这是一个基础编程，但有一点搞不清楚。 if(navigator.appVersion.indexOf("MSIE") != -1) 为什么要不等于-？

搞不清楚，谢谢！！！