JavaScript常用判断写法大全(推荐)

js验证表单大全,用JS控制表单提交，具体内容如下所示：

1. 长度限制

<script>function test() {if(document.a.b.value.length>50){alert("不能超过50个字符！");document.a.b.focus();return false;}}</script><form name=a onsubmit="return test()"><textarea name="b" cols="40" wrap="VIRTUAL" rows="6"></textarea><input type="submit" name="Submit" value="check"></form>

2. 只能是汉字

<input onkeyup="value="/oblog/value.replace(/[^u4E00-u9FA5]/g,'')">

3." 只能是英文

<script language=javascript>function onlyEng(){if(!(event.keyCode>=65&&event.keyCode<=90))event.returnvalue=false;}</script><input onkeydown="onlyEng();">

4. 只能是数字

<script language=javascript>function onlyNum(){if(!((event.keyCode>=48&&event.keyCode<=57)||(event.keyCode>=96&&event.keyCode<=105)))//考虑小键盘上的数字键event.returnvalue=false;}</script><input onkeydown="onlyNum();">

5. 只能是英文字符和数字

<input onkeyup="value="/oblog/value.replace(/[W]/g,"'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^d]/g,''))">

6. 验证邮箱格式

<SCRIPT LANGUAGE=javascript RUNAT=Server>function isEmail(strEmail) {if (strEmail.search(/^w+((-w+)|(.w+))*@[A-Za-z0-9]+((.|-)[A-Za-z0-9]+)*.[A-Za-z0-9]+$/) != -1)return true;elsealert("oh");}</SCRIPT><input type=text onblur=isEmail(this.value)>

7. 屏蔽关键字(这里屏蔽***和****)

<script language="javascript1.2">function test() {if((a.b.value.indexOf ("***") == 0)||(a.b.value.indexOf ("****") == 0)){alert(":)");a.b.focus();return false;}}</script><form name=a onsubmit="return test()"><input type=text name=b><input type="submit" name="Submit" value="check"></form>

8. 两次输入密码是否相同

<FORM METHOD=POST ACTION=""><input type="password" id="input1"><input type="password" id="input2"><input type="button" value="test" onclick="check()"></FORM><script>function check(){ with(document.all){if(input1.value!=input2.value){alert("false")input1.value = "";input2.value = "";}else document.forms[0].submit();}}</script>

够了吧 :)

屏蔽右键 很酷

oncontextmenu="return false" ondragstart="return false" onselectstart="return false"

加在body中

http://hovertree.com/menu/javascript/

2.1 表单项不能为空

<script language="javascript"><!--function CheckForm(){ if (document.form.name.value.length == 0) { alert("请输入您姓名!");document.form.name.focus();return false;}return true;}--></script>