JavaScript就这么回事4：表单 43 表单构成
1: <form method=”post” action=”target.html” name=”thisForm”>
2: <input type=”text” name=”myText”>
3: <select name=”mySelect”>
4: <option value=”1”>First Choice</option>
5: <option value=”2”>Second Choice</option>
6: </select>
7: <br>
8: <input type=”submit” value=”Submit Me”>
9: </form>
44 访问表单中的文本框内容
1: <form name=”myForm”>
2: <input type=”text” name=”myText”>
3: </form>
4: <a href='#' onClick='window.alert(document.myForm.myText.value);'>Check Text Field</a>
45 动态复制文本框内容
1: <form name=”myForm”>
2: Enter some Text: <input type=”text” name=”myText”><br>
3: Copy Text: <input type=”text” name=”copyText”>
4: </form>
5: <a href=”#” onClick=”document.myForm.copyText.value =
6: document.myForm.myText.value;”>Copy Text Field</a>
46 侦测文本框的变化
1: <form name=”myForm”>
2: Enter some Text: <input type=”text” name=”myText” onChange=”alert(this.value);”>
3: </form>
47 访问选中的Select
1: <form name=”myForm”>
2: <select name=”mySelect”>
3: <option value=”First Choice”>1</option>
4: <option value=”Second Choice”>2</option>
5: <option value=”Third Choice”>3</option>
6: </select>
7: </form>
8: <a href='#' onClick='alert(document.myForm.mySelect.value);'>Check Selection List</a>
48 动态增加Select项
1: <form name=”myForm”>
2: <select name=”mySelect”>
3: <option value=”First Choice”>1</option>
4: <option value=”Second Choice”>2</option>
5: </select>
6: </form>
7: <script language=”JavaScript”>
8: document.myForm.mySelect.length++;
9: document.myForm.mySelect.options[document.myForm.mySelect.length - 1].text = “3”;
10: document.myForm.mySelect.options[document.myForm.mySelect.length - 1].value = “Third Choice”;
11: </script>
49 验证表单字段
1: <script language=”JavaScript”>
2: function checkField(field) {
3: if (field.value == “”) {
4: window.alert(“You must enter a value in the field”);
5: field.focus();
6: }
7: }
8: </script>
9: <form name=”myForm” action=”target.html”>
10: Text Field: <input type=”text” name=”myField”onBlur=”checkField(this)”>
11: <br><input type=”submit”>
12: </form>
50 验证Select项
1: function checkList(selection) {
2: if (selection.length == 0) {
3: window.alert(“You must make a selection from the list.”);
4: return false;
5: }
6: return true;
7: }
51 动态改变表单的action
1: <form name=”myForm” action=”login.html”>
2: Username: <input type=”text” name=”username”><br>
3: Password: <input type=”password” name=”password”><br>
4: <input type=”button” value=”Login” onClick=”this.form.submit();”>
5: <input type=”button” value=”Register” onClick=”this.form.action = ‘register.html’; this.form.submit();”>
6: <input type=”button” value=”Retrieve Password” onClick=”this.form.action = ‘password.html’; this.form.submit();”>
7: </form>
52 使用图像按钮
1: <form name=”myForm” action=”login.html”>
2: Username: <input type=”text” name=”username”><br>
3: Password: <input type=”password”name=”password”><br>
4: <input type=”image” src="/”login.gif"” value=”Login”>
5: </form>
6:
53 表单数据的加密
1: <SCRIPT LANGUAGE='JavaScript'>
2: <!--
3: function encrypt(item) {
4: var newItem = '';
5: for (i=0; i < item.length; i++) {
6: newItem += item.charCodeAt(i) + '.';
7: }
8: return newItem;
9: }
10: function encryptForm(myForm) {
11: for (i=0; i < myForm.elements.length; i++) {
12: myForm.elements[i].value = encrypt(myForm.elements[i].value);
13: }
14: }
15:
16: //-->
17: </SCRIPT>
18: <form name='myForm' onSubmit='encryptForm(this); window.alert(this.myField.value);'>
19: Enter Some Text: <input type=text name=myField><input type=submit>
20: </form>