Ueditor How to extract <p> tag strings? or use PHP to extract the string

How to get from

The contents of the tag to extract a fixed number of characters as a post of the introduction? I see Baidu Bar is a post in front of a certain number of characters extracted as a post introduction to display. Let's say the following is an example of content

some content...

...

...

...

...
Due to a

The length of the content in the label is not fixed, and it may start with a picture label, or insert code

Label, and so on, suppose you want to
Extract 50 characters from the tag and don't know if it's OK. If it is not good to deal with, can use PHP efficient processing?
                                                    
                                                                                                                                             
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How to get from
The contents of the tag to extract a fixed number of characters as a post of the introduction? I see Baidu Bar is a post in front of a certain number of characters extracted as a post introduction to display. Let's say the following is an example of content
some content...
 
...
...
...
...
Due to a
The length of the content in the 
   tag is not fixed and may start with the picture   tag, or insert the code   
 
 tag and so on, suppose you want to extract 50 characters from the   
   tag and don't know if it's OK. If it is not good to deal with, can use PHP efficient processing?                                    
 
 
 
 Hello, I feel can use regular to match, and then use Preg to extract the content, if this idea is not possible, you can use JS traversal to do. I hope you will be more specific, I can write a bit. If not, please correct me.                                    
 
                                    
 
 Regular + string intercept 
 
 
 
    
     ]+> (. *?)                                        
     
 
 Simple regular bar. 
 
 
 Assuming that the   
 
 Tag has been found, You can use SUBSTR + strip_tags to do 
 
 How to find   
 
 Tags, you can use regular or phpquery 
 
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