


A problem I encountered today is that I want to get the value in the list sent from the background in js. Originally, the page was displayed using ELexpression, and everything was fine. However, I needed to dynamically obtain the URL in the collection and then call qrcode in js to generate the QR code. When I tried to follow most of the ideas When getting the value, I encountered the following problem
for(var i=0;i<${myTickets.size()};i++) { $('#qrcode'+i).qrcode({text: ${myTickets[i].url}}); }
Hahaha, I used the debugging tool to see that ${myTickets.size()} did get the length of the list, but $ {myTickets[i].url}} cannot get any value!
Then I tried to get the value as follows
[javascript] view plain copy for(var i=0;i<${myTickets.size()};i++) { alert(${myTickets[0].url}) }
Hahaha, it hurts when I take it out. But the problem lies here: when using EL expression ${myTickets[i].url} in for loop, i cannot get the value, which means that EL expression cannot use JS The variable in the EL expression is a whole. Specifically, we can do the following, use foreach in JS to take out the push value into the array, and then loop to traverse the array, which can be a perfect solution:
[javascript] view plain copy var array = new Array(); <c:forEach items="${myTickets}" var="t"> array.push(${t.ticketNo}); //js中可以使用此标签,将EL表达式中的值push到数组中 </c:forEach> for(var i=0;i<array.length;i++) { $('#qrcode'+i).qrcode({text: ctx+"/wxpay/"+array[i]}); }
above I compiled it for everyone. I hope it will be helpful to everyone in the future.
Related articles:
How to use el expressions in <script></script> tags
##Focus on analysis and answers to js and el expression operation list
Detailed introduction to the use of EL expressions in JS
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