Summary of common JavaScript verification function examples_javascript skills

The examples in this article summarize common JavaScript verification functions. Share it with everyone for your reference. The specific summary is as follows:

1. String type verification

1. Length limit

Copy code The code is as follows:

<script><br> function test()<br> {<br> if(document.a.b.value.length>50)<br> {<br> alert("Cannot exceed 50 characters!");<br> document.a.b.focus();<br> return false;<br> }<br> }<br> </script>

2. Can only be Chinese characters

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3." It can only be in English

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4. It can only be numbers

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5. Can only be English characters and numbers

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6. Verify email format

Copy code The code is as follows:

7. Block keywords (*** and **** are blocked here)

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8. Are the passwords entered twice the same?

Copy code The code is as follows:

<script><br> function check()<br> {<br> with(document.all){<br> if(input1.value!=input2.value)<br> {<br> alert("false")<br> input1.value = "";<br> input2.value = "";<br> }<br> else document.forms[0].submit();<br> }<br> }<br> </script>

9. Block right click is cool!

Copy code The code is as follows:

oncontextmenu="return false" ondragstart="return false" onselectstart="return false"

Add to body

2. Form verification

1 form item cannot be empty

Copy code The code is as follows:

2 Compare whether the values ​​of two form items are the same

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3 form items can only be numbers and "_", used for phone/bank account verification, and can be extended to domain name registration, etc.

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4 Form item input value/length limit

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5 Chinese/English/numeric/email address validity judgment

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6 限定表单项不能输入的字符

复制代码 代码如下:

三、其他验证：

1. 检查一段字符串是否全由数字组成 

复制代码 代码如下:

 
2. 怎么判断是否是字符

复制代码 代码如下:

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

 
3. 怎么判断是否含有汉字  

复制代码 代码如下:

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

   
4. 邮箱格式验证   

复制代码 代码如下:

//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;
}

 
5. Digital format verification

Copy code The code is as follows:

//Function name: fucCheckNUM
//Function introduction: Check whether it is a number
//Parameter description: Number to be checked
//Return value: 1 means it is a number, 0 means it is not a number
function fucCheckNUM(NUM)
{
var i,j,strTemp;
strTemp="0123456789";
if (NUM.length== 0)
return 0
for (i=0;i {
j=strTemp.indexOf(NUM.charAt(i));
if (j==-1)
{
//Explain that there are characters that are not numbers
return 0;
}
}
//The description is a number
return 1;
}

 
6. Phone number format verification

Copy code The code is as follows:

//Function name: fucCheckTEL
//Function introduction: Check whether it is a phone number
//Parameter description: String to be checked
//Return value: 1 means legal, 0 means illegal
function fucCheckTEL(TEL)
{
var i,j,strTemp;
strTemp="0123456789-()# ";
for (i=0;i {
j=strTemp.indexOf(TEL.charAt(i));
if (j==-1)
{
//Indicates that some characters are illegal
return 0;
}
}
//Explanation is legal
return 1;
}

7. Function to determine whether the input is Chinese

Copy code The code is as follows:

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

8. Comprehensive function to judge the legality of user input

Copy code The code is as follows:

I hope this article will be helpful to everyone’s web programming based on JavaScript.