基於jQuery實現的,主要用於IE下實現placeholder效果,可同時支持文本和密碼輸入框。placeholder是HTML5新增的一個屬性,當input設置了該屬性後,該值的內容將做爲灰色提示顯示在文本框中,當文本框得到焦點時,提示文字消失。javascript
實現代碼以下: html
var placeholderfriend = {
focus: function(s) {
s = $(s).hide().prev().show().focus();
var idValue = s.attr("id");
if (idValue) {
s.attr("id", idValue.replace("placeholderfriend", ""));
}
var clsValue = s.attr("class");
if (clsValue) {
s.attr("class", clsValue.replace("placeholderfriend", ""));
}
}
}java
//判斷是否支持placeholder
function isPlaceholer() {
var input = document.createElement('input');
return "placeholder" in input;
}
//不支持的代碼
if (!isPlaceholer()) {
$(function() {jquery
var form = $(this);ide
//遍歷全部文本框,添加placeholder模擬事件
var elements = form.find("input[type='text'][placeholder]");
elements.each(function() {
var s = $(this);
var pValue = s.attr("placeholder");
var sValue = s.val();
if (pValue) {
if (sValue == '') {
s.val(pValue);
}
}
});this
elements.focus(function() {
var s = $(this);
var pValue = s.attr("placeholder");
var sValue = s.val();
if (sValue && pValue) {
if (sValue == pValue) {
s.val('');
}
}
});code
elements.blur(function() {
var s = $(this);
var pValue = s.attr("placeholder");
var sValue = s.val();
if (!sValue) {
s.val(pValue);
}
});orm
//遍歷全部密碼框,添加placeholder模擬事件
var elementsPass = form.find("input[type='password'][placeholder]");
elementsPass.each(function(i) {
var s = $(this);
var pValue = s.attr("placeholder");
var sValue = s.val();
if (pValue) {
if (sValue == '') {
//DOM不支持type的修改,須要複製密碼框屬性,生成新的DOM
var html = this.outerHTML || "";
html = html.replace(/\s*type=(['"])?password\1/gi, " type=text placeholderfriend")
.replace(/\s*(?:value|on[a-z]+|name)(=(['"])?\S*\1)?/gi, " ")
.replace(/\s*placeholderfriend/, " placeholderfriend value='" + pValue
+ "' " + "onfocus='placeholderfriendfocus(this);' ");
var idValue = s.attr("id");
if (idValue) {
s.attr("id", idValue + "placeholderfriend");
}
var clsValue = s.attr("class");
if (clsValue) {
s.attr("class", clsValue + "placeholderfriend");
}
s.hide();
s.after(html);
}
}
});htm
elementsPass.blur(function() {
var s = $(this);
var sValue = s.val();
if (sValue == '') {
var idValue = s.attr("id");
if (idValue) {
s.attr("id", idValue + "placeholderfriend");
}
var clsValue = s.attr("class");
if (clsValue) {
s.attr("class", clsValue + "placeholderfriend");
}
s.hide().next().show();
}
});事件
});
}
window.placeholderfriendfocus = placeholderfriend.focus;
})(jQuery);
使用很簡單,html代碼以下: