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IE和FireFox中的textarea长度限制

2011-12-27 21:25 267 查看

	<html>
	<head>
	<title>IE和FireFox中的textarea长度限制</title>
	</head>
	<body>
	<textarea maxlength="20" onpropertychange="onmyinput(this)" oninput="return onmyinput(this)" onPaste="return onmypaste(this);" onKeyPress="return onmykeypress(this);"cols="40" rows="4" ></textarea>
	//功能：IE和FireFox中的textarea长度限制

	<script type="text/javascript">
	function onmyinput(o)
	{
	if(o.value.length>=o.getAttribute("maxlength"))
	{
	if(o.value.length>o.getAttribute("maxlength"))
	o.value = o.value.substring(0,o.getAttribute("maxlength"));
	return false;
	}
	return true;
	}
	function mygetclipdata()
	{
	if(!document.all)
	{
	netscape.security.PrivilegeManager.enablePrivilege('UniversalXPConnect');
	var clip = Components.classes['@mozilla.org/widget/clipboard;1'].createInstance(Components.interfaces.nsIClipboard);
	var trans = Components.classes['@mozilla.org/widget/transferable;1'].createInstance(Components.interfaces.nsITransferable);
	trans.addDataFlavor('text/unicode');
	var str = Components.classes["@mozilla.org/supports-string;1"].createInstance(Components.interfaces.nsISupportsString);
	clip.getData(trans,clip.kGlobalClipboard);
	var str=new Object();
	var strLength=new Object();
	trans.getTransferData("text/unicode",str,strLength);
	if (str)
	str=str.value.QueryInterface(Components.interfaces.nsISupportsString);
	var pastetext;
	if (str)
	pastetext=str.data.substring(0,strLength.value / 2);
	return pastetext;
	}
	else
	{
	return window.clipboardData.getData("Text");
	}
	}
	function mysetclipdata(o)
	{
	if(!document.all)
	{
	netscape.security.PrivilegeManager.enablePrivilege('UniversalXPConnect');
	var clip = Components.classes['@mozilla.org/widget/clipboard;1'].createInstance(Components.interfaces.nsIClipboard);
	var trans = Components.classes['@mozilla.org/widget/transferable;1'].createInstance(Components.interfaces.nsITransferable);
	trans.addDataFlavor("text/unicode");
	var str = Components.classes["@mozilla.org/supports-string;1"].createInstance(Components.interfaces.nsISupportsString);
	str.data=o;
	trans.setTransferData("text/unicode",str,o.length*2);
	var clipid=Components.interfaces.nsIClipboard;
	clip.setData(trans,null,clipid.kGlobalClipboard);
	}
	else
	{
	window.clipboardData.setData("Text",o);
	}
	}
	function onmypaste(o)
	{
	var nMaxLen=o.getAttribute? parseInt(o.getAttribute("maxlength")):"";
	if(!document.all)
	{
	alert("不可能执行的代码");
	}
	else
	{

	if(document.selection.createRange().text.length>0)
	{
	var ovalueandclipboarddata = o.value +window.clipboardData.getData("Text");
	if(o.getAttribute && ovalueandclipboarddata.length-document.selection.createRange().text.length>nMaxLen)
	{
	if(window.clipboardData.getData("Text").substring(0,document.selection.createRange().text.length+nMaxLen-o.value.length)!="")
	window.clipboardData.setData("Text",window.clipboardData.getData("Text").substring(0,document.selection.createRange().text.length+nMaxLen-o.value.length));
	else
	return false;
	}
	}
	else
	{
	var ovalueandclipboarddata = o.value +window.clipboardData.getData("Text");
	if(o.getAttribute && ovalueandclipboarddata.length>nMaxLen)
	{
	if(ovalueandclipboarddata.substring(0,nMaxLen-o.value.length)!="")
	window.clipboardData.setData("Text",ovalueandclipboarddata.substring(0,nMaxLen-o.value.length));
	else
	return false;
	}
	}
	return true;
	}
	}
	function onmykeypress(o)
	{
	if(!document.all)
	{
	var nMaxLen=o.getAttribute? parseInt(o.getAttribute("maxlength")):"";

	if(onmykeypress.caller.arguments[0].ctrlKey == true)
	{
	if(onmykeypress.caller.arguments[0].which==118)
	{

	if(o.selectionStart<o.selectionEnd)
	{
	var ovalueandclipboarddata = o.value + mygetclipdata();
	if(o.getAttribute && (ovalueandclipboarddata.length-o.selectionEnd + o.selectionStart>nMaxLen))
	{
	if(mygetclipdata().substring(0,o.selectionEnd - o.selectionStart+nMaxLen-o.value.length)!="")
	mysetclipdata(mygetclipdata().substring(0,o.selectionEnd - o.selectionStart+nMaxLen-o.value.length));
	else
	return false;
	}
	}
	else
	{
	var ovalueandclipboarddata = o.value +mygetclipdata();
	if(o.getAttribute && ovalueandclipboarddata.length>nMaxLen)
	{
	if(ovalueandclipboarddata.substring(0,nMaxLen-o.value.length)!="")
	mysetclipdata(ovalueandclipboarddata.substring(0,nMaxLen-o.value.length));
	else
	return false;
	}
	}
	return true;

	}
	}


	if(onmykeypress.caller.arguments[0].which==0 \|\| onmykeypress.caller.arguments[0].which==8)
	return true;
	if(o.value.length>=o.getAttribute("maxlength"))
	{
	if(o.selectionStart<o.selectionEnd)
	return true;
	if(o.value.length>o.getAttribute("maxlength"))
	o.value = o.value.substring(0,o.getAttribute("maxlength"));
	return false;
	}
	else
	return true;

	}
	else
	{
	if(document.selection.createRange().text.length>0)
	return true;
	if(o.value.length>=o.getAt 9a27 tribute("maxlength"))
	return false;
	else
	return true;
	}
	}
	</script>
	</body>
	</html>

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标签： firefox ie function object null

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