[英]How to get jQuery placeholder/watermark plugin to work for ajax loaded text fields?
我正在使用以下占位符插件
(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));
它将占位符属性应用于本机不支持占位符属性的浏览器中的表单字段(例如IE9)。 它适用于静态加载的文本字段,但是对于通过ajax加载的文本字段,不会显示占位符。
是否有可能在通过ajax加载的文本字段上实现这种“水印”效果?
在AJAX调用完成后,您可以将插件应用于新创建的控件。 请原谅伪代码,因为我不确定您的AJAX调用是如何工作的:
$.ajax({
url: "test.html",
cache: false
}).done(function( result ) {
field = $('<input>').html(result);
$("#results").append(field);
field.placeholder();
});
另一个选择是你可以使用jQuery的.on()方法将动态创建的控件绑定到函数 - 但它需要一个事件(如click)。 我不确定你会怎么做。 也许是这样的:
$( 'body' ).on('click','input.addField', function(e){
$(this).placeholder();
});
我知道这不起作用,但也许它可以帮助你集体讨论解决方案。
如果在添加新输入后触发窗口调整大小功能会发生什么?
$(window).trigger('resize')
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