java Html&JavaScript面试题：HTML 的 form 提交之前如何验证数值文本框的内容全部为数字? 否则的话提
提交的验证方法（通过单个字符比较）：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
VerifyDate
<form id="form1" action="VefifyData.html">
<input type="text" name="d1" /> <input type="submit" />
</form>
<script type="text/javascript">
document.getElementById("form1").onsubmit = function chkForm() {
var text = this.d1.value;
alert(text.length);
for (i=0;i<text.length;i++) {
alert(i+"的字符是"+text.charAt(i));
if (text.charAt(i) > '9' || text.charAt(i) < '0') {
alert("第 " + i + " 个为非数字字符 "+text.charAt(i));
} else {
alert("第 " + i + " 个为数字字符"+text.charAt(i));
}
}
return false;
}
</script>
</body>
</html>提交验证方法（通过正则表达式）
js中用pattern.test(需要验证字符串) pattern是正则表达式
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
VerifyDate
<form id="form1" action="VefifyData.html">
<input type="text" name="d1" /> <input type="submit" />
</form>
<script type="text/javascript">
document.getElementById("form1").onsubmit = function chkForm() {
var text = this.d1.value;
if(verifyData(text)){
alert("全部为数字...");
return false;
}else{
alert("不全部为数字...");
return false;
};
}
function verifyData(text){
var dataPattern=/^\d[0-9]{0,}$/;
return dataPattern.test(text);
}
</script>
</body>
</html>提交之前验证的方法
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
VerifyDate
<form id="form1" action="http://www.cnblogs.com/qingyundian" onsubmit="return chkForm()">
<input type="text" id="d1" /> <input type="submit" />
</form>
<script type="text/javascript">
function chkForm() {
var text = document.getElementById("d1").value;
alert(text);
if(verifyData(text)){
alert("全部为数字...");
alert("校验成功，之后进行提交...");
return true;
}else{
alert("不全部为数字...");
alert("校验失败，不进行提交");
return false;
}
return false;
}
function verifyData(text){
var dataPattern=/^\d[0-9]{0,}$/;
return dataPattern.test(text);
}
</script>
</body>
</html>这种方法会先校验
校验成功会 返回true 给onsubmit
校验失败会 返回false给onsubmit
校验成功 打开激活网页
