当字符串以“ <”字符开头时，jQuery正则表达式不匹配

Question

I am trying so see if the start of a string has the "<" character, but it will not work. It works fine in regex101.com , but not when I try it in personal files.

Type in a backslash and it works fine, type in a < and it will not work.

 $(function() { $(document).on('keyup', '.input', function() { var str = $(this).html(); // not working if (str.match(/^</)) { console.log('starts with "<" character'); } // but this works?? if (str.match(/^\\\\/)) { console.log('starts with backslash'); } }); }); 

 .input { border: 1px solid #ccc; } 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <div class="input" contenteditable></div> 

Answer 1

Javascript could be encoding the < symbol to < . Try doing console.log(str); to take a look if this is happening (it did when I tried it in my browser).

If that's the case, replace the < symbol with < in your pattern like so:

    if (str.match(/^</)) {
        console.log('starts with "<" character');
    }