检查一段字符串是否全由数字组成<script language="Javascript"><!--
function checkNum(str){return str.match(/\D/)==null}
alert(checkNum("1232142141"))
alert(checkNum("123214214a1"))
// --></script>
function checkNum(str){return str.match(/\D/)==null}
alert(checkNum("1232142141"))
alert(checkNum("123214214a1"))
// --></script>
<head>
<script language=javascript>
function check(){
textvalue=form1.txtTest.value;
for (var i=0;i<textvalue.length;i++){
if ("0123456789".indexOf(textvalue.substring(i,i+1))==-1){
alert("请全部输入数字！");
document.form1.txtTest.value='';
document.form1.txtTest.focus();
break;
}
else{
continue;
}
}
if (textvalue.charAt(0)=="0"){
alert ("第一个数字不可以为0；")
document.form1.txtTest.value='';
document.form1.txtTest.focus();
}}
</script>
</head>
<body>
<form name="form1" action="">
<input type=text size=8 name="txtTest">
<input type="button" value="按钮" name="B1" onclick="check()">
</form >
</body>
</html>