How to check if a string is html or not using JavaScript?
Last Updated :
19 Jan, 2023
The task is to validate whether the given string is valid HTML or not using JavaScript. we’re going to discuss a few techniques.
Approach
- Get the HTML string into a variable.
- Create a RegExp which checks for the validation.
- RegExp should follow the rules of creating an HTML document.
Example 1: In this example, a regexp is created and it is validating the HTML string as valid.
html
< h1 style = "color:green;" id = "h1" >
GeeksforGeeks
</ h1 >
< p id = "GFG_UP" >
</ p >
< button onclick = "GFG_Fun()" >
click here
</ button >
< p id = "GFG_DOWN" >
</ p >
< script >
var up = document.getElementById('GFG_UP');
var str1 = '< div >GeeksForGeeks</ div >';
var str = '< div >GeeksForGeeks</ div >';
up.innerHTML = "Click on the button to check "+
"for the valid HTML.< br > String - " + str1;
var down = document.getElementById('GFG_DOWN');
function GFG_Fun() {
down.innerHTML =
/<(?=.*? .*?\/ ?>|br|hr|input|!--|wbr)[a-z]+.*?>|<([a-z]+).*?<\/\1>/i.test(str);
}
</ script >
|
Output:
How to check if a string is html or not using JavaScript?
Example 2: In this example, Here also, A regexp is created and it is validating the HTML string as invalid.
html
< h1 style = "color:green;" id = "h1" >
GeeksforGeeks
</ h1 >
< p id = "GFG_UP" >
</ p >
< button onclick = "GFG_Fun()" >
click here
</ button >
< p id = "GFG_DOWN" >
</ p >
< script >
var up = document.getElementById('GFG_UP');
var str1 = '< div >GeeksForGeeks</ dv >';
var str = '< div >GeeksForGeeks</ dv >';
up.innerHTML = "Click on the button to check "+
"for the valid HTML.< br > String - " + str1;
var down = document.getElementById('GFG_DOWN');
function GFG_Fun() {
down.innerHTML =
/<([A-Za-z][A-Za-z0-9]*)\b[^>]*>(.*?)<\/\1>/.test(str);
}
</ script >
|
Output:
How to check if a string is html or not using JavaScript?
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