清除默认表单
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
</head>
<body>
<input type="text" style="width:190px; height:16px; color:#DFDFDF" value="本龙练习空间" onfocus="if(this.value=='本龙练习空间'){this.value=''};this.style.color='black';" onblur="if(this.value==''||this.value=='本龙练习空间'){this.value='本龙练习空间';this.style.color='#DFDFDF';}">
<input type=text name="address" size=19 value="Enter,e-mail..."onFocus="this.value=''">
</body>
</html>
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javascript常见的表单输入限制功能,在输入的时候限制用户的输入:
1.文本框只能输入数字代码(小数点也不能输入)
< input onkeyup="this.value=this.value.replace(/\D/g,'')" onafterpaste="this.value=this.value.replace(/\D/g,'')">
2.只能输入数字,能输小数点.
< input onkeyup="if(isNaN(value))execCommand('undo')" onafterpaste="if(isNaN(value))execCommand('undo')">
< INPUT onchange="if(/\D/.test(this.value)){alert('只能输入数字');this.value='';}" name=txt1>
3.数字和小数点方法二
< input type=text tvalue="" ovalue="" onkeypress="if(!this.value.match(/^[\+\-]?\d*?\.?\d*?$/))this.value=this.t_value;else this.tvalue=this.value;if(this.value.match(/^(?:[\+\-]?\d+(?:\.\d+)?)?$/))this.ovalue=this.value" onkeyup="if(!this.value.match(/^[\+\-]?\d*?\.?\d*?$/))this.value=this.t_value;else this.tvalue=this.value;if(this.value.match(/^(?:[\+\-]?\d+(?:\.\d+)?)?$/))this.ovalue=this.value" onblur="if(!this.value.match(/^(?:[\+\-]?\d+(?:\.\d+)?|\.\d*?)?$/))this.value=this.o_value;else{if(this.value.match(/^\.\d+$/))this.value=0+this.value;if(this.value.match(/^\.$/))this.value=0;this.ovalue=this.value}">
4.只能输入字母和汉字
< input onkeyup="value=value.replace(/[\d]/g,'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[\d]/g,''))" maxlength=10 name="Numbers">
5.只能输入英文字母和数字,不能输入中文
< input onkeyup="value=value.replace(/[^\w\.\/]/ig,'')">
6.只能输入数字和英文
< input onKeyUp="value=value.replace(/[^\d|chun]/g,'')">
7.小数点后只能有最多两位(数字,中文都可输入),不能输入字母和运算符号
< input onKeyPress="if((event.keyCode<48 || event.keyCode>57) && event.keyCode!=46 || /\.\d\d$/.test(value))event.returnValue=false">
8.小数点后只能有最多两位(数字,字母,中文都可输入),可以输入运算符号
< input onkeyup="this.value=this.value.replace(/^(\-)*(\d+)\.(\d\d).*$/,'$1$2.$3')">
9.只能输入中文:
< input name="realname" type="text" maxlength="20" value="" onkeyup="value=value.replace(/[^\u4E00-\u9FA5]/g,'')" onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\u4E00-\u9FA5]/g,''))" />