js 点击input和textarea 文本框消失

<input name="shouji" type="text" value="输入手机号简易注册" onclick="clearDefaultText(this,'输入手机号简易注册')"/>

function clearDefaultText (el,message)

{

var obj = el;

if(typeof(el) == "string")

obj = document.getElementById(id);

if(obj.value == message)

{

obj.value = "";

}

obj.onblur = function()

{

if(obj.value == "")

{

obj.value = message;

}

}

}

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<textarea name="morencontect" rows="8" id="contect" onfocus="ClearDefault(this)" onblur="AddDefault(this)">我想旅游</textarea>

var defaultvalue="我想旅游";

function ClearDefault(element)

{

if(element.value==defaultvalue)

{

element.value = "";

}

}

function AddDefault(element)

{

if(element.value=="")

{ element.value =defaultvalue; }

}