输入框添加提示文字
相信每个程序员在写程序时，都会遇到一些这样那样的问题，比如在输入框中添加提示文字等，刚好在做项目时发现了一个
很好用的一个控件，现在分享给大家，希望可以帮到有用的人。
1、引用相应的js，如图所示：
2、添加input输入框，如下所示：
用户名：<input type="text" id="uname"><br/> 密 码：<input type="password" id="pwd">
3、添加对应的script代码，如下所示：
<script type="text/javascript"> $(function(){ $("#uname").watermark("请输入用户名","ccc"); //ccc为样式 $("#pwd").watermark("请输入密码","ccc")； //ccc为样式 }) </script>
<style type="text/css">
.ccc{color:#ccc; font-size:12px;}
</style>
4、显示结果如下：
watermark内容如下所示
/* Watermark v3.1.4 (August 13, 2012) plugin for jQuery http://jquery-watermark.googlecode.com/ Copyright (c) 2009-2012 Todd Northrop http://www.speednet.biz/ Dual licensed under the MIT or GPL Version 2 licenses. */ (function(n,t,i){var g="TEXTAREA",d="function",nt="password",c="maxLength",v="type",r="",u=!0,rt="placeholder",h=!1,tt="watermark",s=tt,o="watermarkClass",w="watermarkFocus",a="watermarkSubmit",b="watermarkMaxLength",e="watermarkPassword",f="watermarkText",l=/\r/g,ft=/^(button|checkbox|hidden|image|radio|range|reset|submit)$/i,it="input:data("+s+"),textarea:data("+s+")",p=":watermarkable",k=["Page_ClientValidate"],y=h,ut=rt in document.createElement("input");n.watermark=n.watermark||{version:"3.1.4",runOnce:u,options:{className:tt,useNative:u,hideBeforeUnload:u},hide:function(t){n(t).filter(it).each(function(){n.watermark._hide(n(this))})},_hide:function(n,i){var a=n[0],w=(a.value||r).replace(l,r),h=n.data(f)||r,p=n.data(b)||0,y=n.data(o),s,u;h.length&&w==h&&(a.value=r,n.data(e)&&(n.attr(v)||r)==="text"&&(s=n.data(e)||[],u=n.parent()||[],s.length&&u.length&&(u[0].removeChild(n[0]),u[0].appendChild(s[0]),n=s)),p&&(n.attr(c,p),n.removeData(b)),i&&(n.attr("autocomplete","off"),t.setTimeout(function(){n.select()},1))),y&&n.removeClass(y)},show:function(t){n(t).filter(it).each(function(){n.watermark._show(n(this))})},_show:function(t){var p=t[0],g=(p.value||r).replace(l,r),i=t.data(f)||r,k=t.attr(v)||r,d=t.data(o),h,s,a;g.length!=0&&g!=i||t.data(w)?n.watermark._hide(t):(y=u,t.data(e)&&k===nt&&(h=t.data(e)||[],s=t.parent()||[],h.length&&s.length&&(s[0].removeChild(t[0]),s[0].appendChild(h[0]),t=h,t.attr(c,i.length),p=t[0])),(k==="text"||k==="search")&&(a=t.attr(c)||0,a>0&&i.length>a&&(t.data(b,a),t.attr(c,i.length))),d&&t.addClass(d),p.value=i)},hideAll:function(){y&&(n.watermark.hide(p),y=h)},showAll:function(){n.watermark.show(p)}},n.fn.watermark=n.fn.watermark||function(i,y){var tt="string";if(!this.length)return this;var k=h,b=typeof i==tt;return b&&(i=i.replace(l,r)),typeof y=="object"?(k=typeof y.className==tt,y=n.extend({},n.watermark.options,y)):typeof y==tt?(k=u,y=n.extend({},n.watermark.options,{className:y})):y=n.watermark.options,typeof y.useNative!=d&&(y.useNative=y.useNative?function(){return u}:function(){return h}),this.each(function(){var et="dragleave",ot="dragenter",ft=this,h=n(ft),st,d,tt,it;if(h.is(p)){if(h.data(s))(b||k)&&(n.watermark._hide(h),b&&h.data(f,i),k&&h.data(o,y.className));else{if(ut&&y.useNative.call(ft,h)&&(h.attr("tagName")||r)!==g){b&&h.attr(rt,i);return}h.data(f,b?i:r),h.data(o,y.className),h.data(s,1),(h.attr(v)||r)===nt?(st=h.wrap("<span>").parent(),d=n(st.html().replace(/type=["']?password["']?/i,'type="text"')),d.data(f,h.data(f)),d.data(o,h.data(o)),d.data(s,1),d.attr(c,i.length),d.focus(function(){n.watermark._hide(d,u)}).bind(ot,function(){n.watermark._hide(d)}).bind("dragend",function(){t.setTimeout(function(){d.blur()},1)}),h.blur(function(){n.watermark._show(h)}).bind(et,function(){n.watermark._show(h)}),d.data(e,h),h.data(e,d)):h.focus(function(){h.data(w,1),n.watermark._hide(h,u)}).blur(function(){h.data(w,0),n.watermark._show(h)}).bind(ot,function(){n.watermark._hide(h)}).bind(et,function(){n.watermark._show(h)}).bind("dragend",function(){t.setTimeout(function(){n.watermark._show(h)},1)}).bind("drop",function(n){var i=h[0],t=n.originalEvent.dataTransfer.getData("Text");(i.value||r).replace(l,r).replace(t,r)===h.data(f)&&(i.value=t),h.focus()}),ft.form&&(tt=ft.form,it=n(tt),it.data(a)||(it.submit(n.watermark.hideAll),tt.submit?(it.data(a,tt.submit),tt.submit=function(t,i){return function(){var r=i.data(a);n.watermark.hideAll(),r.apply?r.apply(t,Array.prototype.slice.call(arguments)):r()}}(tt,it)):(it.data(a,1),tt.submit=function(t){return function(){n.watermark.hideAll(),delete t.submit,t.submit()}}(tt))))}n.watermark._show(h)}})},n.watermark.runOnce&&(n.watermark.runOnce=h,n.extend(n.expr[":"],{data:n.expr.createPseudo?n.expr.createPseudo(function(t){return function(i){return!!n.data(i,t)}}):function(t,i,r){return!!n.data(t,r[3])},watermarkable:function(n){var t,i=n.nodeName;return i===g?u:i!=="INPUT"?h:(t=n.getAttribute(v),!t||!ft.test(t))}}),function(t){n.fn.val=function(){var u=this,e=Array.prototype.slice.call(arguments),o;return u.length?e.length?(t.apply(u,e),n.watermark.show(u),u):u.data(s)?(o=(u[0].value||r).replace(l,r),o===(u.data(f)||r)?r:o):t.apply(u):e.length?u:i}}(n.fn.val),k.length&&n(function(){for(var u,r,i=k.length-1;i>=0;i--)u=k[i],r=t[u],typeof r==d&&(t[u]=function(t){return function(){return n.watermark.hideAll(),t.apply(null,Array.prototype.slice.call(arguments))}}(r))}),n(t).bind("beforeunload",function(){n.watermark.options.hideBeforeUnload&&n.watermark.hideAll()}))})(jQuery,window);
