javascript - Whats the difference between these 2 script If Statements and why 1 of them Wont work -

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  • code 1 (don't care other value expet one, value don't want continue)

    if (!optval == "select report")

  • code 2 (checking options of dropdown way)

    if (optval == "lpr-standard lease report" || optval == "open acreage summary report" || optval == "capital ownership report") {

following this, theres other code runs functionality.

i check value of optval before going if statement chromes built in developer tools. value comes in definatly not select report.

enter image description here

you can see here there not equal , next line not 234, end of if statement below.

code1 seems doesn't matter optval , considered (!optval == "select report")

code2 runs perfect.

i wonder if in javascript (!variable) not permitted have (!variable= value)??

it's order of operations issue, add paren's:

if (!(optval == "select report"))

or use 

if(optval != "select report")

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