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I am getting value from a text field. I have one if and several else if statement. The problem the last else if doesn't execute even if the condition is true. If I change the last else if to if it executes and gives alert. When i change that back to else if the statement doesn't execute. The else if before that is fine as it's firing/executing on a particular condition. function Valcheck() { var txtVal = document.getElementById("sometextField").value; if(txtVal =="%") { alert("% is only allowed with other characters."); return; } else if(txtVal.indexOf("%") != -1) { if((txtVal.indexOf('%')) != (txtVal.length-1)) { alert(" % is only allowed at the end."); return; } } else if(txtVal.indexOf(",") != -1) { alert("Comma or comma separated values are not allowed."); return; }