JavaScript精简学习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='http://www.webjx.com/htmldata/2006-02-06/1139212451.html#' 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=http://www.webjx.com/htmldata/2006-02-06/”#” 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='http://www.webjx.com/htmldata/2006-02-06/1139212451.html#' 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=http://www.webjx.com/htmldata/2006-02-06/”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.value = encrypt(myForm.elements.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>