将变量（文本框）乘以数字并根据文本框中的输入发送警报（如果已满足某些条件）

I have written javascript code that is meant to alert the user if certain conditions are met within textboxes. If those conditions are met the variable 'singlenum' should multiply by 40 and be part of the alert that the webpage (currently doesn't) sends. I have written javascript code that is meant to