<form onsubmit="return check_data()">function check_data()
{
if(document.all["a"].value<document.all["b"].value)
{
return false
alert("a<b")
}
else
{
return ture
}
}
{
if(document.all["a"].value<document.all["b"].value)
{
return false
alert("a<b")
}
else
{
return ture
}
}
A: <input type=text name=t1><br>
B: <input type=text name=t2><br>
<input type=submit value=submit></form><script language=javascript>
function cc()
{
var a = document.all.t1.value;
var b = document.all.t2.value;
if (a=="" || b==""){alert("不能为空");return false;}
if (!(a.match(/\D/)==null) || !(b.match(/\D/)==null))
{alert("你输入的不是数字");return false;}
a = parseFloat(a);
b = parseFloat(b);
if (a < b){alert("a不得小于b");return false;}
return true;
}
</script>