Jquery中文网 www.jquerycn.cn
Jquery中文网 >  jQuery  >  jquery 教程  >  正文 placeholder jquery插件

placeholder jquery插件

发布时间:2016-09-04   编辑:www.jquerycn.cn
jquery中文网为您提供placeholder jquery插件等资源,欢迎您收藏本站,我们将为您提供最新的placeholder jquery插件资源
/*****************************************************************************
jquery Placeholder 1.1.9

Copyright (c) 2010 Michael J. Ryan (http://tracker1.info/)

Dual licensed under the MIT and GPL licenses:

http://www.opensource.org/licenses/mit-license.php

http://www.gnu.org/licenses/gpl.html

------------------------------------------------------------------------------

Sets up a watermark for inputted fields... this will create a LABEL.watermark 
tag immediately following the input tag, the positioning will be set absolute, 
and it will be positioned to match the input tag.

To activate:

	$('input[placeholder],textarea[placeholder]').placeholder();

NOTE, when changing a value via script:

	$('#input_id').val('new value').change(); //force change event, so placeholder sets properly

To style the tags as appropriate (you'll want to make sure the font matches):

	label.placeholder {
		cursor: text;				<--- display a cursor to match the text input

		padding: 4px 4px 4px 4px;   <--- this should match the border+padding 
											for the input field(s)
		color: #999999;				<--- this will display as faded
	}

You'll also want to have the color set for browsers with native support
	input:placeholder, textarea:placeholder {
		color: #999999;
	}
	input::-webkit-input-placeholder, textarea::-webkit-input-placeholder {
		color: #999999;
	}

------------------------------------------------------------------------------

Thanks to...

http://www.alistapart.com/articles/makingcompactformsmoreaccessible

http://plugins.jquery.com/project/overlabel

	This works similar to the overlabel, but creates the actual label tag
	based on the placeholder attribute on the input tag, instead of 
	relying on the markup to provide it.

*****************************************************************************/
(function($){

	var ph = "PLACEHOLDER-INPUT";
	var phl = "PLACEHOLDER-LABEL";
	var boundEvents = false;
	var default_options = {
		labelClass: 'placeholder'
	};

	//check for native support for placeholder attribute, if so stub methods and return
	var input = document.createElement("input");
	if ('placeholder' in input) {
		$.fn.placeholder = $.fn.unplaceholder = function(){}; //empty function
		delete input; //cleanup IE memory
		return;
	};
	delete input;

	//bind to resize to fix placeholders when the page resizes (fields are hidden/displayed, which can change positioning).
	$(window).resize(checkResize);

	$.fn.placeholder = function(options) {
		bindEvents();

		var opts = $.extend(default_options, options)

		this.each(function(){
			var rnd=Math.random().toString(32).replace(//./,'')
				,input=$(this)
				,label=$('<label style="position:absolute;display:none;top:0;left:0;"></label>');

			if (!input.attr('placeholder') || input.data(ph) === ph) return; //already watermarked

			//make sure the input tag has an ID assigned, if not, assign one.
			if (!input.attr('id')) input.attr('id', 'input_' + rnd);

			label	.attr('id',input.attr('id') + "_placeholder")
					.data(ph, '#' + input.attr('id'))	//reference to the input tag
					.attr('for',input.attr('id'))
					.addClass(opts.labelClass)
					.addClass(opts.labelClass + '-for-' + this.tagName.toLowerCase()) //ex: watermark-for-textarea
					.addClass(phl)
					.text(input.attr('placeholder'));

			input
				.data(phl, '#' + label.attr('id'))	//set a reference to the label
				.data(ph,ph)		//set that the field is watermarked
				.addClass(ph)		//add the watermark class
				.after(label)		//add the label field to the page

			//setup overlay
			itemFocus.call(this);
			itemBlur.call(this);
		});
	};

	$.fn.unplaceholder = function(){
		this.each(function(){
			var	input=$(this),
				label=$(input.data(phl));

			if (input.data(ph) !== ph) return;

			label.remove();
			input.removeData(ph).removeData(phl).removeClass(ph).unbind('change',itemChange);
		});
	};

	function bindEvents() {
		if (boundEvents) return;

		//prepare live bindings if not already done.
		$("form").live('reset', function(){
			$(this).find('.' + ph).each(itemBlur);
		});
		$('.' + ph)
			.live('keydown',itemFocus)
			.live('mousedown',itemFocus)
			.live('mouseup',itemFocus)
			.live('mouseclick',itemFocus)
			.live('focus',itemFocus)
			.live('focusin',itemFocus)
			.live('blur',itemBlur)
			.live('focusout',itemBlur)
			.live('change',itemChange);
			;
		$('.' + phl)
			.live('click', function() {  $($(this).data(ph)).focus(); })
			.live('mouseup', function() {  $($(this).data(ph)).focus(); });
		bound = true;

		boundEvents = true;
	};

	function itemChange() {
		var input = $(this);
		if (!!input.val()) {
			$(input.data(phl)).hide();
			return;
		}
		if (input.data(ph+'FOCUSED') != 1) {
			showPHL(input);
		}
	}

	function itemFocus() {
		$($(this).data(ph+'FOCUSED',1).data(phl)).hide();
	};

	function itemBlur() {
		var that = this;
		showPHL($(this).removeData(ph+'FOCUSED'));

		//use timeout to let other validators/formatters directly bound to blur/focusout work
		setTimeout(function(){
			var input = $(that);

			//if the item wasn't refocused, test the item
			if (input.data(ph+'FOCUSED') != 1) {
				showPHL(input);
			}
		}, 200);
	};

	function showPHL(input, forced) {
		var label = $(input.data(phl));

		//if not already shown, and needs to be, show it.
		if ((forced || label.css('display') == 'none') && !input.val())
			label
				.text(input.attr('placeholder'))
				.css('top', input.position().top + 'px')
				.css('left', input.position().left + 'px')
				.css('display', 'block');

		//console.dir({ 'input': { 'id':input.attr('id'), 'pos': input.position() }});
	}

	var cr;
	function checkResize() {
		if (cr) window.clearTimeout(cr);
		cr = window.setTimeout(checkResize2, 50);
	}
	function checkResize2() {
		$('.' + ph).each(function(){
			var input = $(this);
			var focused = $(this).data(ph+'FOCUSED');
			if (!focused) showPHL(input, true);
		});
	}

}(jQuery));
$('#email, #pwd, #re-pwd, #checkcode').placeholder();

via

您可能感兴趣的文章:
关于HTML5 input placeholder 的颜色修改
placeholder jquery插件
jQuery lazyLoad图片延迟加载插件的优化改造方法分享
使用jQuery快速解决input中placeholder值在ie中无法支持的问题
jQuery UI API – 可排序小部件(Sortable Widget)
XMLHttpRequest Level 2 FormData 提交二进制文件
jquery插件lazyload.js延迟加载图片的使用方法
HTML5新知识
jquery实现可拖动DIV自定义保存到数据的实例
jquery插件学习五

[关闭]