仿微博字符限制效果实现代码

var oH2 = $("#spetit_word");//提示文字
var oTextarea = $("#p_qa_content");//输入框
var oButton = $("#bt-ico");//按钮

oTextarea.live("keyup", function () {
Limit(oTextarea, 280, oH2);
})
oButton.live("click", function () {
if (font_count < 0 || font_count == null || font_count == 140) {
Error(oTextarea);
} else {
alert('发布成功！');
}
});

var font_count;

function WordLength(obj) {
var oVal = obj.val();
var oValLength = 0;
oVal.replace(/\n*\s*/, '') == '' ? oValLength = 0 : oValLength = oVal.match(/[^ -~]/g) == null ? oVal.length : oVal.length + oVal.match(/[^ -~]/g).length;
return oValLength
}
function Error(obj) {
var oTimer = null;
var i = 0;
oTimer = setInterval(function () {
i++;
i == 5 ? clearInterval(oTimer) : (i % 2 == 0 ? obj.css("background-color", "#ffffff") : obj.css("background-color", "#ffd4d4"));
}, 100);
}
//obj-要检查的输入框, iNow-多少字, tit-提示框
function Limit(obj, iNow, tit) {
var oValLength = WordLength(obj);
font_count = Math.floor((iNow - oValLength) / 2);
if (font_count >= 0) {
tit.html("你还可以输入<strong>" + font_count + "</strong>字");
return true;
} else {
tit.html("已超出<strong style='color:red'>" + Math.abs(font_count) + "</strong>字");
return false;
}
return font_count;
}