我在将事件侦听器设置为按钮 JS 时遇到问题

Question

When I tried set eventlistener to my button(condition with "^") I got Uncaught SyntaxError: Unexpected token < error at HTMLButtonElement.. What to do I don't know. Thank you in advance)

 op = ["button","#hello","^somefun()","<father"]; var el = document.createElement(op[0]); if(op[s][0] == "#"){ el.id = op[s].substring(1,op[s].length); s++; console.log(s); } // set class of element if(op[s][0] == "."){ el.className = op[s].substring(1,op[s].length); s++; console.log(s,el.style.className); } //set text that will be in element if(op[s][0] == "_"){ el.innerHTML = op[s].substring(1,op[s].length); s++ console.log(s); } //there i got a error! if(op[s][0] == "^"){ s++; el.addEventListener("click",function () { eval(op[s]); }); s++; console.log(s); }

Answer 1

When you put the call to eval , you pass in the full string stored in the array ( "^somefun()" ). ^somefun() is a syntax error. You need to slice the string to exclude the ^ .

Some other things that may need reworking:

• Don't use == , for javascript, use === , it prevents unexpected behavior.
• Don't use eval , most of the time, it is a security concern
• Don't access the characters of a string like an array.

Answer 2

As others pointed out in comments, the issue is with the "op" and this line:

op = ["button","#hello","^somefun()","<father"];

Changing it to:

op = ["button","#hello","^somefun()","<father>"];

Will fix the issue.