1.submit 用于提交表单时 使用 οnsubmit=”“
<form class="form-horizontal" onsubmit="checkform()"><div class="control-group"><label class="control-label" for="inputEmail">Email</label><div class="controls"><input type="text" id="inputEmail" placeholder="Email"></div></div><div class="control-group"><label class="control-label" for="inputPassword">Password</label><div class="controls"><input type="password" id="inputPassword" placeholder="Password"></div></div><div class="control-group"><div class="controls"><label class="checkbox"><input type="checkbox"> Remember me</label><button type="submit" class="btn">Sign in</button></div></div></form>
2.button时使用 onclick()方法
<form class="form-horizontal" ><div class="control-group"><label class="control-label" for="inputEmail">Email</label><div class="controls"><input type="text" id="inputEmail" placeholder="Email"></div></div><div class="control-group"><label class="control-label" for="inputPassword">Password</label><div class="controls"><input type="password" id="inputPassword" placeholder="Password"></div></div><div class="control-group"><div class="controls"><label class="checkbox"><input type="checkbox"> Remember me</label><button type="button" onclick="checkform()" class="btn">Sign in</button></div></div></form>
<script type="text/javascript">function checkform(){a=$("#inputEmail").val();if(a==""){alert('1');}}</script>
