function isPlaceholder(){ var input = document.createElement('input'); return 'placeholder' in input; } if (!isPlaceholder()) {//不支持placeholder 用jquery来完成 $(document).ready(function() { if(!isPlaceholder()){ $("input").not("input[type='password']").each(//把input绑定事件 排除password框 function(){ if($(this).val()=="" && $(this).attr("placeholder")!=""){ $(this).val($(this).attr("placeholder")); $(this).focus(function(){ if($(this).val()==$(this).attr("placeholder")) $(this).val(""); }); $(this).blur(function(){ if($(this).val()=="") $(this).val($(this).attr("placeholder")); }); } }); //对password框的特殊处理1.创建一个text框 2获取焦点和失去焦点的时候切换 $("input[type='password']").each( function() { var pwdField = $(this); var pwdVal = pwdField.attr('placeholder'); pwdField.after('<input class="login-input" type="text" value='+pwdVal+' autocomplete="off" />'); var pwdPlaceholder = $(this).siblings('.login-input'); pwdPlaceholder.show(); pwdField.hide(); pwdPlaceholder.focus(function(){ pwdPlaceholder.hide(); pwdField.show(); pwdField.focus(); }); pwdField.blur(function(){ if(pwdField.val() == '') { pwdPlaceholder.show(); pwdField.hide(); } }); }) } }); }