JavaScript就这么回事4：表单
还是先继续写完JS就这么回事系列吧～
43 表单构成
<form method=”post” action=”target.html” name=”thisForm”>
<input type=”text” name=”myText”>
<select name=”mySelect”>
<option value=”1”>First Choice</option>
<option value=”2”>Second Choice</option>
</select>
<br>
<input type=”submit” value=”Submit Me”>
</form>
44 访问表单中的文本框内容
1: <form name=”myForm”>
<input type=”text” name=”myText”>
</form>
<a href='#' onClick='window.alert(document.myForm.myText.value);'>Check Text Field</a>
45 动态复制文本框内容
<form name=”myForm”>
Enter some Text: <input type=”text” name=”myText”><br>
Copy Text: <input type=”text” name=”copyText”>
</form>
<a href=”#” onClick=”document.myForm.copyText.value =
document.myForm.myText.value;”>Copy Text Field</a>
46 侦测文本框的变化
<form name=”myForm”>
Enter some Text: <input type=”text” name=”myText” onChange=”alert(this.value);”>
</form>
47 访问选中的Select
<form name=”myForm”>
<select name=”mySelect”>
<option value=”First Choice”>1</option>
<option value=”Second Choice”>2</option>
<option value=”Third Choice”>3</option>
</select>
</form>
<a href='#' onClick='alert(document.myForm.mySelect.value);'>Check Selection List</a>
48 动态增加Select项
<form name=”myForm”>
<select name=”mySelect”>
<option value=”First Choice”>1</option>
<option value=”Second Choice”>2</option>
</select>
</form>
<script language=”JavaScript”>
document.myForm.mySelect.length++;
document.myForm.mySelect.options[document.myForm.mySelect.length - 1].text = “3”;
document.myForm.mySelect.options[document.myForm.mySelect.length - 1].value = “Third Choice”;
</script>
49 验证表单字段
<script language=”JavaScript”>
function checkField(field) {
if (field.value == “”) {
window.alert(“You must enter a value in the field”);
field.focus();
}
}
</script>
<form name=”myForm” action=”target.html”>
Text Field: <input type=”text” name=”myField”onBlur=”checkField(this)”>
<br><input type=”submit”>
1 </form>
50 验证Select项
function checkList(selection) {
if (selection.length == 0) {
window.alert(“You must make a selection from the list.”);
return false;
}
return true;
}
51 动态改变表单的action
<form name=”myForm” action=”login.html”>
Username: <input type=”text” name=”username”><br>
Password: <input type=”password” name=”password”><br>
<input type=”button” value=”Login” onClick=”this.form.submit();”>
<input type=”button” value=”Register” onClick=”this.form.action = ‘register.html’; this.form.submit();”>
<input type=”button” value=”Retrieve Password” onClick=”this.form.action = ‘password.html’; this.form.submit();”>
</form>
52 使用图像按钮
<form name=”myForm” action=”login.html”>
Username: <input type=”text” name=”username”><br>
Password: <input type=”password”name=”password”><br>
<input type=”image” src="/”login.gif"” value=”Login”>
</form>
53 表单数据的加密
<SCRIPT LANGUAGE='JavaScript'>
<!--
function encrypt(item) {
var newItem = '';
for (i=0; i < item.length; i++) {
newItem += item.charCodeAt(i) + '.';
}
return newItem;
}
function encryptForm(myForm) {
for (i=0; i < myForm.elements.length; i++) {
1 myForm.elements.value = encrypt(myForm.elements.value);
1}
1}
1
1 //-->
1 </SCRIPT>
1 <form name='myForm' onSubmit='encryptForm(this); window.alert(this.myField.value);'>
1 Enter Some Text: <input type=text name=myField><input type=submit>
20: </form>
