JavaScript常用判断写法大全(推荐)

<script>function test() {if(document.a.b.value.length>50){alert("不能超过50个字符！");document.a.b.focus();return false;}}</script><form name=a onsubmit="return test()"><textarea name="b" cols="40" wrap="VIRTUAL" rows="6"></textarea><input type="submit" name="Submit" value="check"></form>

<input onkeyup="value="/oblog/value.replace(/[^u4E00-u9FA5]/g,'')">

<script language=javascript>function onlyEng(){if(!(event.keyCode>=65&&event.keyCode<=90))event.returnvalue=false;}</script><input onkeydown="onlyEng();">

<script language=javascript>function onlyNum(){if(!((event.keyCode>=48&&event.keyCode<=57)||(event.keyCode>=96&&event.keyCode<=105)))//考虑小键盘上的数字键event.returnvalue=false;}</script><input onkeydown="onlyNum();">

<input onkeyup="value="/oblog/value.replace(/[W]/g,"'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^d]/g,''))">

<SCRIPT LANGUAGE=javascript RUNAT=Server>function isEmail(strEmail) {if (strEmail.search(/^w+((-w+)|(.w+))*@[A-Za-z0-9]+((.|-)[A-Za-z0-9]+)*.[A-Za-z0-9]+$/) != -1)return true;elsealert("oh");}</SCRIPT><input type=text onblur=isEmail(this.value)>

<script language="javascript1.2">function test() {if((a.b.value.indexOf ("***") == 0)||(a.b.value.indexOf ("****") == 0)){alert(":)");a.b.focus();return false;}}</script><form name=a onsubmit="return test()"><input type=text name=b><input type="submit" name="Submit" value="check"></form>

<FORM METHOD=POST ACTION=""><input type="password" id="input1"><input type="password" id="input2"><input type="button" value="test" onclick="check()"></FORM><script>function check(){ with(document.all){if(input1.value!=input2.value){alert("false")input1.value = "";input2.value = "";}else document.forms[0].submit();}}</script>

<script language="javascript"><!--function CheckForm(){ if (document.form.name.value.length == 0) { alert("请输入您姓名!");document.form.name.focus();return false;}return true;}--></script>

<script language="javascript"><!--function CheckForm()if (document.form.PWD.value != document.form.PWD_Again.value) { alert("您两次输入的密码不一样！请重新输入.");document.ADDUser.PWD.focus();return false;}return true;}--></script>

<script language="javascript"><!--function isNumber(String){ var Letters = "1234567890-"; //可以自己增加可输入值var i;var c;if(String.charAt( 0 )=='-')return false;if( String.charAt( String.length - 1 ) == '-' )return false;for( i = 0; i < String.length; i ++ ){ c = String.charAt( i );if (Letters.indexOf( c ) < 0)return false;}return true;}function CheckForm(){ if(! isNumber(document.form.TEL.value)) { alert("您的电话号码不合法！");document.form.TEL.focus();return false;}return true;}--></script>

<script language="javascript"><!--function CheckForm() { if (document.form.count.value > 100 || document.form.count.value < 1){ alert("输入数值不能小于零大于100!");document.form.count.focus();return false;}if (document.form.MESSAGE.value.length<10){ alert("输入文字小于10!");document.form.MESSAGE.focus();return false;}return true;}//--></script>

<SCRIPT LANGUAGE="javascript"><!--function isEnglish(name) //英文值检测{ if(name.length == 0)return false;for(i = 0; i < name.length; i++) { if(name.charCodeAt(i) > 128)return false;}return true;}function isChinese(name) //中文值检测{ if(name.length == 0)return false;for(i = 0; i < name.length; i++) { if(name.charCodeAt(i) > 128)return true;}return false;}function isMail(name) // E-mail值检测{ if(! isEnglish(name))return false;i = name.indexOf(" at ");j = name dot lastIndexOf(" at ");if(i == -1)return false;if(i != j)return false;if(i == name dot length)return false;return true;}function isNumber(name) //数值检测{ if(name.length == 0)return false;for(i = 0; i < name.length; i++) { if(name.charAt(i) < "0" || name.charAt(i) > "9")return false;}return true;}function CheckForm(){ if(! isMail(form.Email.value)) { alert("您的电子邮件不合法！");form.Email.focus();return false;}if(! isEnglish(form.name.value)) { alert("英文名不合法！");form.name.focus();return false;}if(! isChinese(form.cnname.value)) { alert("中文名不合法！");form.cnname.focus();return false;}if(! isNumber(form.PublicZipCode.value)) { alert("邮政编码不合法！");form.PublicZipCode.focus();return false;}return true;}//--></SCRIPT>

<script language="javascript"><!--function contain(str,charset)// 字符串包含测试函数{ var i;for(i=0;i<charset.length;i++)if(str.indexOf(charset.charAt(i))>=0)return true;return false;}function CheckForm(){ if ((contain(document.form.NAME.value, "%()><")) || (contain(document.form.MESSAGE.value, "%()><"))){ alert("输入了非法字符");document.form.NAME.focus();return false;}return true;}//--></script>

<script language="Javascript"><!-- function checkNum(str){return str.match(/D/)==null} alert(checkNum("1232142141")) alert(checkNum("123214214a1")) // --></script> 

if (/[^x00-xff]/g.test(s)) alert("含有汉字"); else alert("全是字符"); 

if (escape(str).indexOf("%u")!=-1) alert("含有汉字"); else alert("全是字符"); 

//函数名：chkemail //功能介绍：检查是否为Email Address //参数说明：要检查的字符串 //返回值：0：不是 1：是 function chkemail(a) { var i=a.length; var temp = a.indexOf('@'); var tempd = a.indexOf('.'); if (temp > 1) { if ((i-temp) > 3){ if ((i-tempd)>0){ return 1; } } } return 0; } 

//函数名：fucCheckNUM //功能介绍：检查是否为数字 //参数说明：要检查的数字 //返回值：1为是数字，0为不是数字 function fucCheckNUM(NUM) { var i,j,strTemp; strTemp="0123456789"; if ( NUM.length== 0) return 0 for (i=0;i<NUM.length;i++) { j=strTemp.indexOf(NUM.charAt(i)); if (j==-1) { //说明有字符不是数字 return 0; } } //说明是数字 return 1; } 

//函数名：fucCheckTEL //功能介绍：检查是否为电话号码 //参数说明：要检查的字符串 //返回值：1为是合法，0为不合法 function fucCheckTEL(TEL) { var i,j,strTemp; strTemp="0123456789-()# "; for (i=0;i<TEL.length;i++) { j=strTemp.indexOf(TEL.charAt(i)); if (j==-1) { //说明有字符不合法 return 0; } } //说明合法 return 1; } 

function ischinese(s){ var ret=true; for(var i=0;i<s.length;i++) ret=ret && (s.charCodeAt(i)>=10000); return ret; } 

<script language="javascript"> //限制输入字符的位数开始 //m是用户输入，n是要限制的位数 function issmall(m,n) { if ((m<n) && (m>0)) { return(false); } else {return(true);} } 

function issame(str1,str2) { if (str1==str2) {return(true);} else {return(false);} } 

function notchinese(str){ var reg=/[^A-Za-z0-9_]/g if (reg.test(str)){ return (false); }else{ return(true); } }

function dovalidate(){fm=document.forms[0] //只检测一个form,如果是多个可以改变判断条件for(i=0;i<fm.length;i++){ //检测判断条件，根据类型不同可以修改if(fm[i].tagName.toUpperCase()=="INPUT" &&fm[i].type.toUpperCase()=="TEXT" && (fm[i].title!=""))if(fm[i].value="/blog/="")//{str_warn1=fm[i].title+"不能为空!";alert(str_warn1);fm[i].focus();return false; }if(fm[i].id.toUpperCase()=="SZ")//数字校验{if(isNaN(fm[i].value)){ str_warn2=fm[i].title+"格式不对";alert(str_warn2);fm[i].focus();return false;}}}return true;}