Hi Sahil,
    Go through the example below.

   Apexclass:

public class SearchTextInVFPage{
    public ApexPage vflist {get;set;}
    public ApexPage vfpage {get;set;}
    public string searchstring {get;set;}
    public SearchTextInVFPage(){
        vfpage =new ApexPage();
    }
    public PageReference SearchText()
      {
        system.debug('&&&&&&&'+searchstring );
        vflist =[SELECT ApiVersion,ControllerKey,ControllerType,Description,isAvailableInTouch,IsConfirmationTokenRequired,Markup,MasterLabel,Name,NamespacePrefix from ApexPage where name=:'SearchTextInVFPage'];
        system.debug('................'+ vflist);
        string searchstring1=searchstring.toLowerCase();
        string searchstring2=searchstring.toUpperCase();
       // searchstring=searchstring.equalsIgnoreCase(searchstring);
        if(vflist.Markup.contains(searchstring)==true ||vflist.Markup.contains(searchstring1)==true ||vflist.Markup.contains(searchstring2)==true)
        {
            system.debug('search string present in visualforce page');
        }
        else
          system.debug('search string not there in visualforce page');
       
      
        return null;
      }
}

visualforce page :

<apex:page controller="SearchTextInVFPage">
  <apex:form >
     <apex:inputText value="{!searchstring}"/>
      <apex:commandButton value="Search" action="{!SearchText}"/>
      <br/>
           test
       </apex:form>
 
</apex:page>

run the vf page and check.You can modify as you like.
The content of vf page will be in Markup field.

if this provides you with useful information and if this is what you where looking for then please mark it as a solution for other benefits.