JavaScript 控制文本框的值连续加减

<title>JavaScript控制文本框的值连续加减</title> <script language="javascript"> var flag1=0; var flag2=0; function NumberInc() { if(flag1==1 && flag2==1) {alert("Error!");} else { if(flag1==1) { document.all.TextBox1.value++; setTimeout("NumberInc()",100); } if(flag2==1) { document.all.TextBox1.value--; setTimeout("NumberInc()",100); } } } function md(obj) { if(obj.id=="Button1") flag1=1; if(obj.id=="Button2") flag2=1; NumberInc(); } function mo(obj) { if(obj.id=="Button1") flag1=0; if(obj.id=="Button2") flag2=0; } </script> <html> <body> <form runat=server> <input id="TextBox1" runat="server" Width="50" CssClass="mybutton" Text=0> <input type="button" ID="Button1" value="＋" onMouseDown="md(this)" onMouseOut="mo(this)" onMouseUp="mo(this)" > <input type="button" ID="Button2" value="－" onMouseDown="md(this)" onMouseOut="mo(this)" onMouseUp="mo(this)" > </form> </body> </html>
[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]