[转]js使用技术二则（textarea域自动扩展及数组去重）

//数组去重 利用了原型，对象字面量
Array.prototype.unique = function() {
var newArray = [], temp = {};
for (var i = 0, len = this.length; i < len; i++) {
temp[typeof(this[i]) + this[i]] = this[i];
}
for (var item in temp) {
newArray.push(temp[item]);
}
return newArray;
};
 

//去除字符串前后空格
String.prototype.trim=function(){
  return this.replace(/(^\s*)|(\s*$)/g, "");
};

//textarea域自动扩展 需搭配jquery下使用
(function($) {
// jQuery plugin definition
$.fn.TextAreaExpander = function(minHeight, maxHeight) {
var hCheck = !($.browser.msie || $.browser.opera);
// resize a textarea
function ResizeTextarea(e) {
// event or initialize element?
e = e.target || e;
// find content length and box width
var vlen = e.value.length, ewidth = e.offsetWidth;
if (vlen != e.valLength || ewidth != e.boxWidth) {
if (hCheck && (vlen < e.valLength || ewidth != e.boxWidth)) e.style.height = "0px";
var h = Math.max(e.expandMin, Math.min(e.scrollHeight, e.expandMax));
e.style.overflow = (e.scrollHeight > h ? "auto" : "hidden");
e.style.height = h + 5 + "px";
e.valLength = vlen;
e.boxWidth = ewidth;
}
return true;
};
// initialize
this.each(function() {
// is a textarea?
if (this.nodeName.toLowerCase() != "textarea") return;
// set height restrictions
var p = this.className.match(/expand(\d+)\-*(\d+)*/i);
this.expandMin = minHeight || (p ? parseInt('0'+p[1], 10) : 0);
this.expandMax = maxHeight || (p ? parseInt('0'+p[2], 10) : 99999);
// initial resize
ResizeTextarea(this);
// zero vertical padding and add events
if (!this.Initialized) {
this.Initialized = true;
$(this).css("padding-top", 0).css("padding-bottom", 0);
$(this).bind("keyup", ResizeTextarea).bind("focus", ResizeTextarea);
}
});
return this;
};
})(jQuery);
// initialize all expanding textareas
jQuery(document).ready(function() {
jQuery("textarea[class*=expand]").TextAreaExpander();
});